Large area of saline-alkali land exists in the world, high density salt stress leads to the plant growth retarded, even leads to the death. The crops plants cultivated in the saline-alkali land often occurred a wide range underproduction. One of the main methods to solve this problem is to produce excellent stress-tolerant crops. Using molecular biology, molecular genetics and genetic engineering methods to obtain the stress-tolerant crops in one of the most important aspects in modern agriculture. In this research, Oryza sative L. and mangrove Bruguiera sexangula were used as experimental materials to study mechanism of stress tolerance of plants. The main results were summarized as follows:1.A salt-tolerance related gene ZRP4 was cloned from rice cDNA by using RT-PCR. The full-length of ZRP4 gene, 1101 bp in length, enconding a deduced 366 amino protein which was directed by O-methlytransferanse. In salt stress, the activity of methlytransferanse was injusted to restore the injure of protein. In this research, plant expressing vector and RNAi expressing vector ZRP4 gene were constructed and transferred into rice by Agrobacterium-mediated to obtain the transformed ZRP4 gene rice and ZRP4 gene RNAi transgenic rice. The salt-tolerance ability test of transgenic T_1 and T2 generation plant indicated that, in the 150 mmol/L NaCl stress after 20 days cultivation, the salt-resistance ability of overexpressing ZRP4 gene rice were improved in the salt stress, and the survival rate of transgenic plants were 60%, on the other hand, the untransformed plants were all dead. In the ZRP4 gene RNAi transgenic rice, the activity of methlytransferanse was restrained availably, which can hinder methlytransferanse to restore the injure of protein, all of these related to its resistance ability were depressed and were sensitive to salt stress observably. In the 100 mmol/L NaCl stress after 20 days cultivation, 60% survival rate of the