Aiming at the problem of illumination image estimation in low-light image enhancement algorithm of the Retinex model, a low-light image enhancement method based on YCbCr color space is proposed. The original low-light image is transformed from RGB (Red Green Blue) color space to YCbCr color space. The Y component in YCbCr color space is extracted and the initial illumination map L₁(x, y) is constructed. The enhanced illumination image L₂(x, y) is obtained by the gamma transformation of L₁(x, y), the enhanced image R(x, y) is obtained according to the Retinex model, and we use a multi-scale approach to boost the details of the image R(x, y) and obtain the final enhanced image R_e(x, y).The experimental results show that, the method can not only effectively improve the brightness of the low-light images, enhance the details of the image, obtain a better visual effect with fewer color and lightness distortions, but also has a faster running speed.