In order to investgate the mechanical properties of silicone rubber based coatings at high temperatures,two types of silicone rubber based thermal protective coatings were investigated by high temperature compression tests.The macroscopic morphology and microstructure of the compression sections after high temperature compression were observed.Combined with the analysis of thermal weight loss at high temperature, the mechanism of thermo-mechanical property change was discussed.The results show that the thermal pyrolysis temperature range of methyl phenyl silicone rubber based coating is mainly about 500 to 650 ℃,and the final mass residual rate is 67.61%.The compressive strength increases with the temperature from 25 to 800 ℃.The strength has a decrease from 400 to 700 ℃ beacuse of the softening of the glass microsphere and the thermal pyrolysis reaction of the silicone rubber.At 800 ℃,the compression strength reaches significant increase as a result of the co-melting of glass microsphere,reinforcing fillers and the ablation products. The thermal pyrolysis reaction temperature range of methyl vinyl silicone rubber based coating is 450 to 800 ℃, and the final mass residual rate is 89.95%.After thermal pyrolysis reaction, methyl vinyl silicone rubber transforms from organic to new ceramic phase,which prevents the decrease of the strength caused by resin pyrolysis.Thus the thermo-mechanical properties of methyl vinyl silicone rubber based thermal protective coatings stay steady from 25 to 800 ℃.The mechanism analysis indicates that the main influencing factors of thermo-mechanical properties are pyrolysis of resin matrix and physicochemical changes of fillers under high temperature conditions.