Theory of intergroup contact is one of the most influential theories in social psychology, it has been widely used to practice to reduce prejudice. Contact hypothesis has been confirmed by a large number of empirical researches, it is suitable for different social situations and communities. Secondary transfer effect refers to the positive effects of intergroup contact from direct contact with outgroup to another outgroup not involved in the contact. STE of intergroup contact not only exists in direct contact, also exists in indirect contact, including the extended contact and imaginative contact. With the constant improvement of intergroup contact theory, foreign researchers began to explore the psychological mechanism of secondary transfer effect, discovered the secondary transfer effect produced by some intermediary variables, and influenced the effect of the size of the moderation variables. Through literature analyzed, STE effect not only had individual level factors (social identity complexity), and group level variables (intergroup empathy and intergroup anxiety), and there were aspects of the social environment variable (multiculturalism), including intergroup empathy and intergroup anxiety, it was intergroup interaction of emotional factors to directly affect the STE. In addition, , primary groups influenced STE attitude itself (attitude generalization). Discussed the intervening variable STE could better understand the mechanism of its role in the group attitude. Moderation variable is affecting the relationship between independent variable and dependent variable size or direction of the positive and negative factors found to adjust variables, at the time of practice intervention, will be changed to adjust the size of variables, to influence the size of the relationship between independent variable and dependent variable or direction, realize the intervention effect of optimization. From the point of view of the current research progress, moderation variables of the secondary transfer effect mainly included individual factors and community factors, namely the individual holding group status、social dominance orientation、group similarity, and so on. Future studies should be comprehensive transection and longitudinal research design, such as survey methods and experimental methods. To measure the intergroup contact and group attitude from multiple dimensions in the primary group contact measurement, not only considering the quality and quantity, contact and subjective topic should be used as a supplement of intergroup contact test, could better reflect the extent to which individuals and groups outside the contact. Using different attitude scale attitude measured outside the primary group and secondary group respectively. To explore the mediation and moderation mechanism of STE, it is necessary in a pluralistic society background of developing cross-cultural research and expanding the category of the secondary outside groups and providing scientific theory basis for improving intergroup relationships. In sum, STE of intergroup contact was widespread, and played an important role in the development of intergroup relations. Based on mediation and moderation mechanism in the STE, the psychological mechanism of STE provided a new approach to improve intergroup relations.