At present， there is the lack of effective technical means in the multi-target processing capacity test for infrared warning system. The index is evaluated by inputting single background image simulated by computer. A kind of mathematical model about multi-target generating real-time based on background estimation technique is put forward in this paper， and the real-time test evaluation is realized based on a real sequence image. The method is verified by the real-time experimental data. The results show that the method can effetively detect the multi-target processing ability of the infrared warning system on the basis of greatly saving troops， and provide technical and theoretical support for the improvement of equipment simulation training system.