Abstract: Based on Fuzzy Analytical Hierarchy Process (FAHP), a influencing model for organizational factors on system safety in nuclear power plant was established, and its index system was determined. With the computing program, the relative influence degree of the factor, the entire influence degree of the factor and the importance degree of the factor were obtained to represent the influence degree of the organizational factor on the system safety. By adopting the method of influence degree of the factor, the influence of the organizational factors on the safety of some nuclear power plant system was analyzed. Results show that supervision, safety culture training, leader's attitude toward the safety, the integrity of the procedure, the communications and feedbacks among the departments, the personnel's consciousness and attitude, the pre-work skill training, the communications and feedbacks inside the department are the most important organizational factors that influence the operational safety of the nuclear power plant.