Acculturation in psychology research focuses on the psychological and behavioral changes of members of different cultural groups due to cultural shock in direct contact,and it reflects the harmony between individuals and their original culture and the new culture.The process of acculturation may not merely influence individuals' physical and psychological health,but also affect their interpersonal interaction and social adaptation,even ethnic relations.In the multi-cultural environment of China,compared with cultures of other ethnic minorities, ban culture occupies dominance.Although the tolerance of han culture implies the integration of different ethnic cultures,the differences between han and ethnic minorities' cultures still exist,in that the latter appear more exclusive and unique.Therefore,when ethnic minority members enter ban culture from their familiar original culture,acculturation problems due to culture shock may occur.In addition,a review of ethnic minorities' mental health studies find some ethnic minority members tend to develop more serious mental problems than han individuals,which partly reflects the existence of acculturation problems of ethnic minorities as well.Moreover,it is found there exists scarcity of psychological researches of ethnic minorities' acculturation in China,thus a psychology research on acculturation carries certain practical and theoretical value.Southwest China is diverse in ethnic cultures and the traditional ethnic culture there is kept relatively perfect.Although under great impact of han culture,compared with ethnic members with lower education and fewer chances to get in touch with han culture,ethnic minority college students develop a better understanding of culture shock thanks to their knowledge enrichment and independent thinking development.Therefore,a research of ethnic minority college students' acculturation in this area will be more representative.Thus,in the context of multi ethnic cultures in southwest China,this research conducts a systematic study on ethnic minority college students' acculturation from the perspective of psychology.The research adopts questionnaire survey,field work,interview,and literature study and centers on acculturation modes,acculturative stress and the stages of acculturation.Furthermore,based on the findings of pragmatic researches and relevant literature study,suggestions and countermeasures are made to promote positive acculturation and mental health of ethnic college students.On the basis of the concepts of acculturation in related theories as well as the aim,subjects and cultural background of this research,acculturation is defined as a harmonious psychological and behavioral involvement in both original ethnic culture and han culture of ethnic minority individuals during cultural change,in which psychological involvement refers to positive identity with cultures,and behavioral involvement refers to active participation in cultures.An ideal state of acculturation is such that individuals possess a harmonious relation with the original and the new cultures,or the integration mode proposed by acculturation theory,which is to hold positive identity with and active participation in both original and new cultures.In the structure of ethnic diversity and unity in China,the key in the ideal acculturation of ethnic minorities is to develop a harmony between individuals and the original ethnic culture and the han culture.This research mainly consists of six aspects.The first is the research on the acculturation modes of ethnic minority students.Based on the bi-dimensional model of acculturation theory,acculturation mode here refers to the different patterns resulted from the differences in original ethnic culture and han culture identity and participation of acculturating ethnic minority members.This research adopts questionnaire developed to conduct a survey of a sample of ethnic students in certain colleges in southwest China, and classifies the data collected,the classification analysis of which partly consists with the theoretical hypothesis.It turns out to be three modes of identity acculturation,integration, separation and marginalization,four modes of behavioral acculturation,integration,separation, assimilation and marginalization,and in general acculturation modes there mainly appear five patterns,bi-integration,bi-separation,bi-marginalization,instrumental integration and instrumental assimilation.There exist characteristics and demographic traits in these modes.The second is the research of acculturative stress of ethnic minority college students. Acculturative stress here refers to ethnic students' difficulties and confusions resulted from cultural differences during acculturation process.Through a questionnaire survey,it is found that acculturative stress experienced by ethnic students are composed of three main elements,language stress,prejudice and cultural loss worries.An overall analysis of acculturative stress shows that the acculturative stress of ethnic students ranges from mild to moderate in degrees,and there exist individual differences as well.The third is an analysis on the relevance between acculturation and acculturative stress,which adopts difference test,correlation analysis,and path analysis to study the relation between acculturation modes and acculturative stress,dimensions of acculturation and acculturative stress, and the influence of these dimensions on acculturation.Path analysis indicates behavioral acculturation exerts greater impact on prejudice,so an effective way to eliminate prejudice is to increase equal and cooperative behavioral involvement in multi-cultural activities.The fourth is a case study of ethnic college students in Lancang Lahu autonomous county and Menghai county in Yunnan province.Based on field work and interviews,the stages of ethnic students' identity and behavioral acculturation change are analyzed,as well as the cultural background and other affecting factors of acculturation,and the difficulties in acculturation.And the approach of field work turns out to be effective supplement to the research.The fifth is a study of ethnic college students' cognition of "han-ization",which analyzes the relevance between "han-ization" and acculturation.It turns out that the ethnic students surveyed tend to regard it as behavioral assimilation,and in identity,it is not the identity with han culture with the discard of original ethnic culture,instead it is more likely to be integration in identity,with both han and ethnic cultures.Anyhow,ethnic students investigated make a high judgment of their degree of han-ization,especially in ethnic customs and language,so there is necessity to protect ethnic cultures.Lastly countermeasures are suggested as for ethnic college students' mental health service in school on the basis of the above research results and related literature reviews.The suggestions center on the following three aspects,more and deeper relevant mental health studies on ethnic student,the construction of multicultural mental health service and development of ethnic students' multicultural competence.Besides,according to the specific case in the field work,it is proposed that school mental health education not merely promotes the understanding and status of ethnic college students' mental health,but also may contribute to the mental health competence of other ethnic minority members under the influential role of ethnic minority college students in their ethnic community.