It is valuable to realize that a family not only is the most basic and vital units of the society, but also has a far–reaching influence on development of the individual. Under the psychological field of vision, the parental marital conflict is a key point which has effect the stability of family systems. Moreover, many empirical studies indicate that marital conflict is associated with adolescent aggressive behavior . At the same time, the peer is also increasingly important in determining adolescents academic, physical, and socio–emotional well–being. Based on the family systems theory, the present study investigated the mediating effect of deviant peer affiliation on the relationship between parental marital conflict and adolescent aggressive behavior, and impulsivity ’s moderation of the effect of peer context. Children’s Perception of Inter–parental Conflict Scale(CPIC), the Negative Urgency– Premeditation–Perseverance–Sensation seeking–Positive Urgency (UPPS–P) Scale, aggressive behavior questionnaire and deviant peer affiliation questionnaire were administered to 1406 adolescents (Mean age =12.90, male =699)from junior middle school in Guangdong province in southern China. Chi–square test and t test showed that there were no differences between students who lost to attrition gender, age and other variables in this study. The assessment was conducted in class. All materials and procedures were approved by the Ethics in Human Research Committee of author’s university. The results presented mean, standard deviations, and the bivariate correlations between the variables involved in this study. Path analyses were tested to use the bootstrapping method in the structural equation modeling software Mplus 7.1, with the full–information maximum likelihood estimation. Congruent with our hypothesis, the mediation model seems to perfectly fit the data: x2/df= 2.012, CFI= .99, RMSEA= .027. The bias–corrected bootstrapping result indicated that the indirect effect of parental marital conflict on adolescent aggressive behaviors through deviant peer affiliation was significant (standardized indirect effect = .02; 95% CI [ .001, .02]). As shown in results, consistent with the hypothesized pathway, when controlling for gender, age and family income, parental marital conflict was positively associated with adolescents deviant peer affiliation which in turn was related to aggressive behaviors. In summary, the current study goes beyond previously applied designs by examining the mediating mechanism caused by deviant peer affiliation, and represents an important step in the investigation of how parental marital conflict relates to adolescent aggressive behaviors by moderation of impulsivity. The findings highlight the importance of marital conflict and deviant peer affiliation under the context of Chinese culture. It is so important to get the awareness which improve the family atmosphere and make the better peer affiliation would be more effective in reducing aggressive behaviors among adolescent with high impulsivity. These ?ndings demonstrate that intervention and prevention programs aimed at reducing adolescent aggressive behaviors must be all–sided and incorporate the impact of family, peer, and individual characteristics.