To address the challenges of combining medium and long wave dual-band infrared pseudo-color images that contain blurred fusion information and insignificant characterizations, this paper presents an all-informative color mapping algorithm. The algorithm provides practical value for color mapping of fused infrared images by analyzing the relationship between balanced color adjustment and preservation of source image data, ensuring that the pseudo-color fusion effect in infrared images highlights the difference in information across various bands while also complying with human visual perception. The algorithm is based on vectors of gray scale variations that are mapped to color in the HIS color space, with the final display in the RGB color space. Simulation and experimental results indicate the effectiveness of the algorithm. The algorithm has also been used in a real-time dual-band infrared color fusion system using FPGA hardware design for engineering purposes.