This study aimed to predict aggressive behaviors of students based on family cohesion, among secondary school students first base was the ninth in Kahnooj city. The sample consisted of 270 female students of high school (ninth base) Kahnooj city who were selected by simple random sampling. In this study was used to collect data from Boss and Perry's Aggression Questionnaire, Questionnaire family cohesion . And to analyze the collected data, the simultaneous linear regression, Pearson correlation coefficients were used. Spss20 and statistical software was used for data analysis. Analysis of main assumptions identified that there is a significant negative relationship between family cohesion with aggressive students. And finally the general regression model, two variables of family cohesion could negatively predict aggression.