【Abstract】 Objective： Cooperation is a complex interaction which plays an important role in the development of child socialization. Cooperation must have two or more independent body and the motivation to force them together. The study on cooperative behavior can retrospect to the late 19th century. Previous studies focused on adult cooperation mechanism through the experimental model of social dilemmas, or focused on the development of child cooperative behavior through the games and activities observation. The paper explore the relationship between children’s interpersonal trust, achievement motives and the tendency of cooperation behavior and attitude. Method：553 students of grade 3 to grade 8 completed Achievement motive scale, children’s Machiavellism scale, the Interpersonal Trust Scale, cooperative behavior and attitude questionnaire ,Two measurement ways were used in this study, self-rating and peer rating. Results：1, There is polarization in Children’s attitude on human nature when they enter a junior high school. The boy’s trust score is stabile, but the girl’s trust score is fluctuant.2, there is significant sexual difference in the development tendency of achievement motive. 3,The level of achievement motive for success is positively correlated with all of cooperative tendency and ability, the level of achievement motive for obviating failure is negative correlated with self-rating cooperative tendency. Conclusion：Interpersonal trust and achievement motives play an important role in children’s cooperation behavior. It is Achievement motive which play more important role than Interpersonal trust in the children cooperative behavior tendency.