Endoscopic image quality plays an important role in the diagnosis of early lesions and dysplasia. Therefore, a blood vessel enhancement algorithm based on spectral absorption characteristics of blood vessels is proposed in this paper. First of all, RGB channels are obtained from the color image and divided into the brightness layer with the high dynamic range and the detail layer with the detail image information through the guided filter. Then, the detail layer of each channel is adaptively enhanced based on SNR (signal noise ratio), and the brightness layer is stretched to improve the GB channel information and to reduce R channel information. Finally each channel is merged to generate an enhanced image. In this article, a large number of endoscopic images is applied to this algorithm and compared with Karl Stroz's Spectra B enhancement technology. This method performs better in image enhancements while using the Detail Variance-Background Variance index and the Weber contrast index to evaluate.