The Relation among Social Withdrawal, Peer relationship and Social-information-processing in Middle Childhood Liu Aishu1, Yu Zengyan2, Yang Feilong1, Pei Liang1 (1Department of Psychology, School of Education, Harbin Normal University, Harbin, 150025) (2Department of Psychological Medicine, Qiqihar Medicine College, 161006) Abstract As the psychological and social risks associated with social withdrawal have become clear, social withdrawal has become a very important issue in developmental psychology and cross-cultural psychology since 1980s.?It has been found that socially withdrawn school-aged children were reported more negative self-perceptions, greater feelings of social anxiety and loneliness, higher rates of depression, and are more likely to be rejected by peers than their non-withdrawn classmates. Several factors have been proposed that may underlie the development and display of social withdrawal in childhood, including biological and physiological factors, as well as parental beliefs and practices. Another process that might underlie the development of social withdrawal is children's social information processing abilities. However, there has been surprisingly little research exploring the social information processing of socially withdrawn children. Although certain characteristics of SIP may place withdrawn children at risk for maladjustment, it is also important to assess those factors that can protect children from maladaptive social interpretations and coping strategies. One such protective factor for socially withdrawn children may be friendship. As such, the purpose of this study was to explore peer relationships and social information processing of the different types of social withdrawal in middle childhood, and to find the relations between peer relationships and social information processing of withdrawn children. Class Play Scale was used to screen 121 socially withdrawn children from 929 children from Grade 3 to Grade 5, and the control group was established. Peer Nomination, Friend Nomination and Friendship Quality Questionnaire were administrated to all the children and structural interview of social information processing was used to part of them. The results indicated that: 1.The peer relationships of passive withdrawn children, which weren’t significantly different from the control group, were best among the different types of socially withdrawn children, but that of active withdrawn children and mixed withdrawn children were worse than the control group. There was no significant difference on social status, mutual friends and friendship quality between passive withdrawn children and control children; 2.In general, withdrawn children showed lower level of ability to encode information, a preference for non-assertive, withdrawn problem-solving strategies to deal with hypothetical conflict situations, reported lower self-efficacy to act chosen response and had more performance deficits compared with control children. But among all subtypes of socially withdrawn children, active withdrawn children and mixed withdrawn children had more cognition deficits at the different steps of SIP model, such as more hostile attributions pattern, less response quantity. 3.The part mediator effect of peer relationships between social withdrawal and social information processing was confirmed; Multiple regression analysis showed that peer relationships and ability to act upon his chosen response could predict the socially withdrawn behavior negatively and strongly.