The dynamic simulation of IR sea background is an important part of simulation of 3D sea battlefield environment, which has great application value. A simulation method of dynamic infrared sea background was presented in this paper, which achieved a lifelike sea surface real-time simulation. The texture of sea waves was generated based on normal map technique and the dynamic rendering sea surface by introducing shader programming based on GPU. In shaders, the radiation character, intensity and direction were calculated according to pixel normal. In order to construct sea scene with large area, view detector coordinate detecting technique was proposed. The experiment shows that the rendering speed of infrared sea scene created by the method can achieve the effect of facula and fish scale wave on mid band sea surface, and the frame rate meets the requirement of real-time simulation.