Abstract: In order to distinguish the target of the illumination image better、increase the contract and enhance the weak information, by using sub-layer segmentation and histogram specification to enhance image, we propose the image enhancement combined sub-layer segmentation with histogram specification induced by adaptive function algorithm.Firstly, according to the features of the original image, its histogram will be divided into sub-layer.Then, stretching gradation interval of the sublayer to increase the image brightness, the image contrast can be enhanced.To enhance the image details better, we use the required adaptation functions to do the histogram specification in each sublayer.Finally, the sub-layer histogram will be merged to get the enhanced image.Experimental results show that the gray mean gradient value of the enhanced image was 3-4times of the original image, and entropy was increased obviously.The algorithm can enhance image detail and improve image contrast with superiority.