To effectively evaluate the safety risk status and optimize safety management strategies in university laboratories，a dynamic safety assessment method was proposed based on a multi-layered safety control structure model. Firstly，a multi-layer safety control structure model was developed to identify the causal factors and control deficiencies of fire and explosion accidents in the university laboratory. Then，a safety dynamic feedback evaluation method was developed integrating an accident model based on system theory and Bayesian networks. Finally，the proposed evaluation model was used to determine the risk probability，analyze risk factors affecting safety incidents，and identify key risk factors in university laboratory safety. The results indicated that the proposed evaluation method based on the safety control structure model covered all risks identified by traditional methods and identified potential risks. Furthermore，the incorrect operation of hazardous chemicals，violation of operation procedures during the experiment，and the aging，short circuits，or defects in electrical lines were key risk factors affecting laboratory safety risks of universities.