Abstract: In order to study the energy distribution and other parameters of 1.06μm and 10.6μm lasers in the laser semi-active guidance,a new measurement was put forward based on gray photograph.The influence of laser on the target temperature distribution and the receiving property of infrared video camera was discussed in detail.A mathematical model from optical signal to electric signal to image signal is built up.For a certain 10.6μm laser guided-instrument,its output was simulated according to the model.The obtained result was similar to the actual outcome and the 2-demension correlative coefficient was 0.88995.The result shows that the model is correct and it can be used to test the 1.06μm and 10.6μm lasers.