In the conditions of low temperature and low pressure, the white hydrated calcium silicate powder was produced through the dynamic hydrothermal synthesis technology. Through studying the properties of hydrated calcium silicate powder which is made by different synthesis temperature and the influence of hydrated calcium silicate powder,calcium carbonate and quartz powder on the mechanical properties of silicone rubber, it is found that the hydrated calcium silicate powder which is produced at （120±5）℃ has better performance enhancement. Besides the size of particle, the surface reactivity is also an important factor.