The radiation environment of space accounts much for ultraviolet Photomultiplier Tube (PMT) performance degradation and even invalidation. The ultraviolet PMT's anti-radiation shielding methods depend on the environment of space radiation, spacecraft's orbital altitudes and their life expectancy as well as the type of ultraviolet PMT. Energetic particles environment of the sun synchronous orbit and Monte-Carlo simulation calculation are used in simulating PMT model's shielding effects. Our calculation results are supported an optimization design of shielding compositions for UV PMT on Sun-synchronous orbit. The simulations have determined an optimized shield constituted by an Aluminum-Tungsten-Aluminum tri-layer. And each thickness is 2mm, 0.5mm, 2mm. In a sun-synchronous environment, the dose received by PMT will be decreased from 9.98× 10
6rad to 8.41× 10
2rad, and this optimized multilayer structure could meet our performance requirements.