Focusing on the issue that existing algorithms of infrared and visible image fusion cannot retain thermal radiation information from infrared images, an image fusion algorithm based on thermal radiation information retention was proposed. Multi-scale decomposition of infrared and visible light images was performed through NSCT transformation to obtain the respective high-frequency sub-bands and low-frequency sub-bands. The low-frequency sub-bands of visible light were extracted by the Laplacian and superimposed with the infrared low-frequency sub-bands to obtain low-frequency sub-bands of the fused image. The fusion rule, which is based on point sharpness, and detail enhancement were used to obtain the high-frequency coefficients of the high-frequency part; the fused image was then reconstructed through inverse NSCT transformation. The experimental results indicate that compared with other image fusion algorithms, the proposed algorithm can retain the thermal radiation information of infrared images, while maintaining good performance with clear details, and is superior to other algorithms in several objective evaluation indices. The proposed algorithm has better visual effects and a good visual experience after pseudo-color transformation, which verifies the effectiveness and feasibility of the proposed algorithm.