Social adjustment refers to the individual who interacting with the social environment, by adapting to or changing environment, regulate itself, finally to achieve and maintain a harmonious social environment, balance the dynamic relationship.For pre-school children just enter kindergarten from family, social ability, the internalize and externalize problem behaviors are three important index of preschool children’s social adjustment. Preschool children's social maladjustment are are closely related to many behavioral problems and academic adjustment difficulties in the future.Therefore, to explore the influence factors of preschool children's social adjustment is very necessary and improtant. Previous researches have discussed the relationship between parenting stress and preschool children's social adaptation in different components under the background of the west,but lacked researches discusses the relationships between normal children’s mother parenting stress and children’s social adaptation, and sexual difference,under the background in Chinese culture. 202 preschool children (108 boys, Mage=48.67±2.56 months) and his mother took part in a one-year longitudinal study. At two time points mothers completed Parenting Stress Index (PSI) and Social Competence and Behavior Evaluation(SCBE). All the measures had good reliability and validity. We use Amos24.0 software to run cross-lagged model test.The results showed that: (1) for boys, parenting stress and children’s externalizing problem can predict each other, for girls, parenting stress and children’s externalizing problem behaviors can not predict each other; (2) mother parenting stress and preschool children's social ability can predict each other; (3) mother’s parenting stress can not positively predict children’s internalizing problem behaviors, but children’s internalizing problem behaviors can significantly predict mother’s parenting stress. In summary, mother's parenting stress and children's social adaptation have mutual predictive relationships .Mother parenting stress affected more boy’s externalizing problems, the boy's externalizing problems were also more likely to lead to a mother's stress experience.This study also suggests that, we should not ignore the adverse emotional experience of mother in nurturing and also should pay more attention to the negative effects of mother’s parenting stress on boy’s externalizing problem behaviors.