Chemical agents with high refractive index, hyperosmotic, and biocompatibility are introduced into tissue, which will
reduce the scattering of tissue, and enhance the penetration of light in tissue. Diffuse reflectance, as a common method,
has been applied to assess optical clearing of skin in vivo, but the scattering characteristic during the in-vivo optical
clearing process has not been valuated quantitatively. In this work, a diffuse reflectance spectroscopy, based on a lookuptable (LUT) based inverse model, is applied to calculate the reduced scattering coefficient and absorption coefficient of skin. Optical clearing agents (OCAs) were topically treated on mouse skin in vivo. The diffuse reflectance during optical clearing was recorded, and the optical properties can be extracted by the reflectance spectroscopy. The results show that the diffuse reflectance spectra and the reduced scattering coefficient are decreased obviously, whilst the absorption coefficient is increased after the application of OCAs. This study provides evident directly for explore the mechanisms of optical clearing of skin in vivo.