Gasket is one of the key components in proton exchange membrane fuel cells (PEMFCs), and the performance of the gasket can directly affect the durability and electrochemical performance of the PEMFCs. In this paper, the silicone rubber material, which is being considered as gasket material for PEMFC, was fabricated with different composite reinforcing fillers at different vulcanizing temperatures under different vulcanizing pressures. Effects of the composite reinforcing fillers (i.e., gas-phase SiO 2 and nano-CaCO 3 ), vulcanizing temperatures, and pressures on mechanical properties of the silicone rubber material were investigated. The tensile, hardness measurement, compression set, and compression stress relaxation experimental results show that the mass ratios of the gas-phase SiO 2 to nano-CaCO 3 , curing temperatures, and pressures had a significant impact on the mechanical properties of PEMFC gasket materials. It is found that the silicone rubber material cured at a vulcanization temperature of 160 C and a vulcanization pressure of 10 MPa had good compression mechanical properties compared to the materials cured at the other curing temperatures and curing pressures. Orthogonal test results show that, when mass ratio of the gas-phase SiO 2 to nano-CaCO 3 was 25:20, the silicone rubber material cured at the curing temperature of 160 C and under the curing pressure of 10 MPa had good compressive stress relaxation performance in this work.