The purpose of this study is to examine the relationship among reticent and solitary-passive behavior and adjustment in Chinese children, and the moderate effect of gender. Participants are 145 children (M=129 months, SD=6.5, 60 boys and 85 girls) in Beijing, China. Children were invited to visit the university laboratory and play in quartet, and all sessions were videotaped. Reticent and solitary-passive behaviors were assessed on the basis of children’s behaviors during two free-play sessions in a battery of laboratory observation procedure, using the Play Observation Scale. After the observation procedure, children were asked to fill out some questionnaire which assessed children’s loneliness, depression and self worth. Participants’ teachers were visited and asked to report children’s academic achievements, leadership and school adaptation abilities and problems. It was found that reticent behavior was positively associated with internalizing problems(r=0.41, p<0.01) and victimization(r=0.39, p<0.01) and negatively associated with school adaptation ability(r=-0.36, p<0.05) for boys but not for girls, whereas solitary-passive behaviors was positively associated with indicators of adjustment problems such as loneliness(r=0.30, p<0.01) and depression(r=0.29, p<0.01), and negatively associated with school adaptation abilities(r=-0.29, p<0.05) and leadership(r=-0.31, p<0.05) for girls but not for boys. These results are not consistent with those findings from research conducted in western countries and indicate that the adjustment outcomes of reticent and solitary-passive behaviors are defined by cultural context. The results also indicate that gender may play an important role in defining the functional meanings of children’s social behaviors.