Illumination processing method based on image processing technology is studied. Histogram equalization is effective for treating too bright or too dark background images but is very poor in detail treatment. Retinex is effective in restoring image details. Combining histogram equalization and Retinex, a fusion method is proposed based on wavelet transform. The corresponding experiments were conducted on Yale B face database. The comparison of the experiments showed that the fusion method can weaken the impact of the light on the image, properly preserve the details with better effect of processing, enhance the image feature information and improve the clarity of the image.