Cirrus is mainly composed of non-spherical ice crystals in various shapes and plays an important roles in Earth's radiation budget and global climate change. Knowledge of cirrus properties is crucial for studying the radiation budget and climate change. Thus studies of the optical， microphysical， and physical properties of cirrus have become the popular issue. The optical properties of cirrus at 0.865μm are studied. And the reflectance and polarized reflectance are evaluated with the adding-doubling method by solving the vector radiative transfer model， and the sensitivity of reflectance and polarized reflectance to cirrus optical parameters and surface albedo are evaluated. The results indicate that the polarized reflectance over a large range of scattering angles can show the information of cirrus properties. Based on the studies of the sensitivity， the basic theory of using the remote sensing data of multi-angular polarized measurements to retrieve the properties of cirrus is proposed.