Aiming at the effectiveness of anti-submarine warfare patrol aircraft using homing depth charge and sonobuoy system, the effectiveness evaluation model based on Monte Carlo was designed. First, based on the anti-submarine coordinates, shoot-depth of sequential bomb-dropping was defined; the distribution of guided depth charges and submarine targets directed by sonobuoy system was given; Then, the anti-submarine effectiveness was simulated according to the operation process of guided depth charges and hit qualification; Finally, the availability of this method was proved by results of the simulation, and a method of getting the charge-dropping interval in multi-charge-dropping was proposed.