This paper uses two different preparation processes, precipitated and fumed silica, to prepare polydimethylsiloxane silicone rubber materials. Through the tests of physical property, electrical property, crosslinking density, and static contact angle, the similarities and differences of the various types of silica in reinforcing silicone rubber are analyzed, and the mechanism is explained. According to the relevant experimental data, the hydrophobicity of silicone rubber supplemented with precipitated silica and fumed silica is similar. The electrical properties of fumed silica are more stable and can play a better role in mechanical reinforcement. This study can help clarify the mechanism underlying the function of silica in silicone rubber materials and provide a direction for improving the properties of silicone rubber.