In order to evaluate ship-air missile weapon system’s effectiveness scientifically, a method of ship-to-air missile weapon system effectiveness random simulation and valuation based on test result data was introduced. Constitution and combat process of ship-to-air missile weapon system were first introduced, and then overall thinking of the method was put forward. The random simulation method of ship-to-air missile weapon system was deeply researched, and the weapon system effectiveness evaluation program was developed. The certain type ship-to-air missile weapon’s effectiveness evaluation is taken as the example to validate the effectiveness of evaluation. The research result could effectively support ship-to-air missile weapon system effectiveness evaluation and also provide a reference for other weapon system’s effectiveness evaluation.