The present study was conducted with the aim of investigating the effect of parent-child conflict and the original family function on aggression with the mediation of identity styles in female students. The statistical population of the study was comprised of senior high school students in Kermanshah city. In order to draw the sample, cluster random sampling method was utilized and 384 students were selected. The research instruments included Eysenck & Glyn Wilson’s Aggression Questionnaire (1975), Parent-Child Relationship Scale (Fine et al., 1983), the Family-of-Origin Scale (Hovestadt et al., 1985) and Identity Style Inventory (Berzonsky et al., 2013). The reliability and validity of the research tools was confirmed through content validity, confirmatory factor analysis and calculation of Cronbach's alpha coefficient. Data analysis was done using structural equation modeling (SEM) and partial least squares (PLS) using SPSS25 and Smartpls3 software. The results of the research indicated that the parent-child conflict and original family function directly and indirectly had an impact on the aggression of female students of senior high school students through identity styles. Accordingly, it can be concluded that it is possible to reduce students’ aggression by diminishing the parent-child conflicts, strengthening the family function and also directing identity styles in a proper way.