Moral is a praxis spirit. The moral acquisition of an individual is a process of the social moral being transformed to the individual moral belief and becoming moral characters of that individual through practice. It is also a process of individual moral improvement. The two polarities of rationality and irrationality, which form the human spiritual structure, dialectically and harmoniously influence this process. The main focus of this thesis is to research on the role of human irrationality in the individual moral acquisition. Research in this perspective has been largely ignored theoretically and empirically.Individual moral acquisition is the process of the formation of moral cognition, moral sentiments, and moral will. Moral cognition is the key to and precondition of individual moral acquisition. Moral cognition process includes human sentiments, and will. The formation of moral sentiments is based on moral cognition, and becomes the motive to transform perception to action. Moral will is the key to the transform perception to action. It controls the moral sentiments. Human irrationality has two aspects, psychology and perception. In moral perception the role of irrationality acts as the psychological background of moral cognition in the form of perceptional diagrams, affecting the formation of individual moral acquisition on one hand. On the other hand, in the moral cognition process, the unconsciousness influences the individual perception by way of the mind set, and at the same time the sentiment influences through the intensity of feelings the acceptance, experience, judgment, and transformation of moral cognition by an individual. The will controls sentiments, and sets the course for moral actions depending upon the power of the will of the individual. The influence of individual irrationality makes an individual to show different moral cognition from identical situation, or information. Under the influence of moral sentiments and moral will, irrationality transforms perception to action and make perception and action consistent.The analysis of the role of irrationality in the individual moral acquisition will provide a fresh perspective and a new method in the enhancement and improvement of moral education. The research on irrationality should be enhanced. A coaching style should be adopted to distill into the moral awareness and action. The individual fundamental moral sentiments should be increasingly developed. The formation of individual moral belief should be actively guided. All these methods should be employed to leverage and promote irrationality in the moral education, increase the effectiveness of moral education, and improve the individual moral.