To further improve the brightness, contrast and definition of the low light image effectively, a low light image enhancement method based on weighted plateau histogram equalization is proposed. Taking full advantage of that the lightness component V is independent of the hue H and the saturation S in the HSV color space, this method converts the image to HSV color space, and by the bilateral filtering which has good edge-preserving ability, the lightness component V is decomposed into illumination image L and reflection image R with Retinex algorithm. The illumination image L is subjected to the weighted dual plateau histogram equalization, in which, the upper plateau threshold and the lower plateau threshold are determined adaptively by the principle of 3σ in normal distribution, and the weighting coefficient is inversely proportional to the histogram frequency of the gray level. The experimental results show that compared with some existing methods, the effect of image enhanced by the proposed method is better, and the corresponding information entropy and average gradient are higher than the existing methods by more than 0.35 and 12, respectively, which proves that the proposed method has better low light image enhancement performance.