In the current mainstream medium and long wave color fusion algorithms, except a few color mapping algorithms take the difference features of the source images as the starting point, others such as color transfer algorithms often lose more difference and detail features. However, mainstream color mapping algorithms have some problems such as color bias, narrow color gamut, and difficulty in adapting to various application scenarios. In this paper, the above problems are studied. In the color space based on a hue saturation color plane, a theoretical model of helical line mapping based on difference features is established, and a fusion algorithm is proposed based on this theoretical model. The actually collected medium and long wave dual-band images are simulated and verified. The simulation results show that the proposed algorithm is suitable for most complex scenes and can fully highlight the difference components of infrared mid-wave images. The proposed algorithm has wider color gamut distribution, better visual effect, and better objective index evaluation, and has low computational complexity and high real-time performance. Finally, the embedding of the algorithm is completed on the embedded platform. The results show that the algorithm has the premise of engineering application.