This study has demonstrated that in-situ and ex-situ methods were applied to modify silica particles to improve the reinforcement of silicone rubber. The results show that ex-situ modification maintained silica particles’ spherical shape and in-situ modification tends to preparing silica particles with irregular shape and higher BET surface area. The BET surface area value was 600.57 m2/g, which exceeded 2-fold compared with that of ex-situ modified silica particles. Moreover, the in-situ modified silica particles exhibited a remarkable advantage in reinforcing silicone rubber than the ex-situ modified silica particles owing to irregular shape and higher BET surface area, which can be confirmed by vulcanizing, mechanical properties and thermal stability.