To study the strength degradation law of reactive powder concrete (RPC) after elevated temperatures, the mass loss and compressive strength as well as split-tensile strength of RPC specimens after elevated temperatures were measured. Besides, the effects of temperature and fiber content on the strength of RPC samples were analyzed. The results show that the apparent color of RPC specimens gradually changes from dark to light, and the mass loss rate gradually increases with the rising temperature. The cubic strength loss rate and split-tensile strength loss rate as well as axial compressive strength loss rate all decrease first and then increase with the increasing temperature, but the critical temperature is different. The critical temperature of cube compressive strength and split-tensile strength is 300 ℃, while the critical temperature of axial compressive strength is 200 ℃. In addition, the loss rate of axial compressive strength is higher than that of cubic compressive strength after 300 ℃, and all the strength loss rates exceed 80% after 800 ℃. Deterioration of matrix microstructure is the root cause of macroscopic strength degradation. Moreover, the strength loss rate of the RPC specimen mixed with polypropylene (PP) fiber is relatively small after elevated temperature. When the steel fiber content is 2%（volume fraction), the optimal content of PP fiber is 0.15% （volume fraction). Finally, the calculation equation between the strength loss rate of RPC and temperature as well as PP fiber content was established through regression analysis.