We present a. detailed investigation on the optical properties, including dielectric function, reflectivity, absorption, refractive index, and electron energy-loss spectrum, of the high-pressure phase SnO2 in the rutile, pyrite, fluorite and cotunnite Structures by using the density functional theory (DFT) plane-wave pseudopotential method. The results indicate that with the increasing of pressure the band gaps become larger, the density of states are broader, so the curves of optical properties have a little blue shift. Except that the fluorite phase has some metallic properties, the other three phases exhibit excellent dielectric behavior. Interestingly, the fluorite and cotunnite SnO2 phases always have sonic special characteristics, such as higher plasma frequency, which need further fundamental and application research.