The development of a noval intelligent and modular automatic gun tower system is of great significance to protect national territorial sovereignty. Aiming at the problem that the existing attack effectiveness evaluation systems of gun tower are too complicated and do not possess good real-time performance, the short-range and long-range attack effectiveness evaluation criteria based on infrared image is proposed. And the long-range attack effectiveness evaluation criteria is verified by digital experiments through computer programming. This criterion establishes a digital model based on the influence of various factors, combines them to calculate the probability value that the target groups are loss of combat capability, and finally converts the probability value into the corresponding attack effectiveness evaluation value. The digital experiments for the target group of three people show that, the combat effectiveness evaluation value are 24.8, 20.3, and 4.6 respectively under the loss of combat capability with 0, 1, and 2 person, which meet the long-range combat effectiveness evaluation criteria, and has theoretical research significance and engineering application value for realizing automatic strike.