Abstract: Optical clearing can effectively control the optical properties of in tissue using the optical immersing technique by hyperosmotic agents and be paid more and more attention in the biomedical and optical field. This mothed could reduce the number of the multiple scattered photons, increase the depth of the optical imaging, and get a better contrast grade of images. We measured the change of the optical properties of the tissue of the different depth during the optical clearing process using optical coherence tomography (OCT). We applied the gradient of the OCT signal algorithm to analyze the temporal and spatial distribution of the scattering coefficient during the clearing process. It was demonstrated experimentally that optical clearing could effectively improve the OCT imaging depth. During the process of the optical clearing, the scattering coefficient, the range and the time and the trend of the change of the scattering coefficient changed with the different depth, which was related to the tissue microstructure, the clearing effect due to the microstructure and the diffuse process of the agent. The results could be used to understand the process and the mechanism of the optical clearing.