Abstract: This study aimed to investigate the causes and factors affecting job stress of the staff of PNU in West Province Fars was conducted in 2015. Job Stress Questionnaire of the UK Health and Safety Executive and job stress questionnaire approved by the American Institute of Job Stress were used to evaluate the severity of stress and its related factors and finally, the questionnaire according to the cultural, social, economic conditions was prepared and distributed among the population who were 110 managers and staff of Payam Noor University in West province Fars. To answer questions and check hypotheses Smart-PLS Software throughcheck structural equations and path analysis using Partial Least Squares (PLS) were used. The results show that the dimensions of clarity in the role, authorities’ support of staff, partners’ support of staff and low control of work processes have a significant negative impact on job stress variable. The results also show that the poor relations in the workplace have a significant positive impact on job stress variable. In the end, the results did not confirm the impact of the aspects of demand for one’s job and awareness of changes on the variable job stress.