Abstract: For the case of gas explosion accident in Babao Coal Mine, based on the basic principles of safety control theory, we summarize the reasons of the control failure in system safety from four aspects, including control object, control action, control model and state observation, and propose a new accident analysis method to identify risk factors, find out the safety constraint conditions, set up the safety control system, identify failure safety control and analyze the cause of the failure, and also propose the safety measures. The new method provides a new idea to find safety defects in safety systems, and find out the reasons of the accidents, and prevent such accidents.