Focused on the low-light images obtained from dynamic range, illumination condition, image acquisition equipment, etc., a feature enhancement derivative fusion algorithm based on luminance evaluation technology was proposed to achieve contrast adjustment and feature enhancement of the low-light images. Firstly, the brightness evaluation technique was used to optimize the brightness of the low-light image to obtain the exposure ratio map. Then, combining exposure ratio map and improved chi-square distribution function model, two derivatives with enhanced features were obtained for fusion. Finally, the fusion image was obtained by using the improved derivative fusion algorithm. The experimental results indicate that the proposed algorithm achieves the better results including brightness order error, visual information fidelity and image mutual information, improves the image contrast while preserving the well-exposed region, and it can recover the edge and texture details of the low-luminance region.