The invention relates to a phase modifier fracture circuit breaker flashover fault dynamic simulation system and method. A flashover fault generator unit is used for simulating a circuit breaker flashover fault occurring in the phase modifier grid connection process. The flashover fault generator unit is bridged at the two ends of the phase modifier fracture circuit breaker. One end of the flashover fault generator unit is connected with the equivalent phase modifier group physical simulation unit, and the other end of the flashover fault generator unit is connected with the equivalent power system physical simulation unit. The flashover fault generator unit is also connected with a controller. According to the technical scheme provided by the invention, the fracture flashover fault is prevented from damaging operation equipment, the correctness of the circuit breaker flashover protection action is checked in a laboratory, and the circuit breaker flashover protection can be effectivelychecked.