Infrared imaging of SF6 gas is easily affected by environmental noise and exhibits low contrast and signal-to-noise ratio. As a result, existing algorithms cannot adaptively enhance the SF6 leakage area or suppress Gaussian noise. Therefore, this study proposes an improved HE-based SF6 leakage-area enhancement algorithm. The algorithm first uses SSR to process the original SF6 image to obtain the reflection image R, and then uses guided filtering to decompose the reflection image R into detail and base layers. Finally, an improved histogram equalization is used to adaptively process the base layer, and the enhanced images are fused to obtain the final image. The experiment results demonstrate that the proposed algorithm can not only adaptively enhance the contrast of the leaked area but also has good edge preservation and Gaussian noise suppression performance. Its enhancement effect is superior to that of the existing SF6 infrared image enhancement algorithm. This effectively improves the low-contrast and low signal-to-noise ratio characteristics of the SF6 infrared images.