A model of fault diagnosis for power system based on time sequence fuzzy Petri net is proposed, which mainly includes identifying blackout area, modeling for time sequence fuzzy Petri net of possible faulty components, solving faulty component set and judging operation information of protection and circuit breakers. Fault alarm error information classification and fault alarm information timing characteristics are introduced. Based on the study of operation information of circuit breakers and network topology, the method for identifying blackout area is given with BFS. Finally, take New England 10 machine 39 node system as an example, mathematical models of fault diagnosis for power lines and bus on time sequence fuzzy Petri net are established, and the overall structure of this system is given, results show that it can rapidly locate fault, and accurately give operation information of protection and circuit breakers.