The purpose of this article is studying the impact of human resource activities on organizational performance. In this regard, the impact of social capital and psychological capital on organizational performance, have been studied; thus one time considered as a independent variables and again considered as mediating variables in the relationship between human resource activities and organizational performance. This is an applied research. The population of research is all of the staff of the university of Lorestan. Random sampling is used. Questionnaire was the main tool for gathering primary data. Data analysis is done based on Structural Equation Modeling. The results show that human resource practices are extremely important in organizations, so that human resource practices with the regression coefficient of 0.84 affect on organizational performance and with the regression coefficient of 0.56 and 0.61 affect on social capital and psychological capital. In addition, social capital and psychological capital with regression coefficient of 0.66 and 0.75 affect on organizational performance. It should be noted that social capital and psychological capital, play the mediating role in the relationship between human resource practices and organizational performance.