In order to explore the mechanical strength degradation characteristics of rubber concrete (RC) after high-temperature, the mass loss, compressive strength, splitting tensile strength and flexural strength of RC with different supplementary cementitious materials (SCMs) under high-temperature were tested, and the effects of temperature and SCMs on RC strength were analyzed. The results indicate that as the temperature increases, the color of RC specimens gradually lightens from dark to light, accompanied by varying degrees of cracking, spalling, and mass loss, with severe deterioration occurring at 800 ℃. The mass loss rate of RC peak at 700 ℃. Rubber particles and SCMs improve the failure mode of RC and enhance residual strength before 200 ℃, but mechanical strength of RC sharply declines after 400 ℃. Scanning electron microscopy analysis reveals that high-temperature leads to the increase of internal pores and cracks in RC, and the deterioration of the microstructure is the main cause for the degradation of macroscopic mechanical strength of RC. Based on the experimental data, functional formulas have been established between temperature and the loss rates of cubic compressive strength, splitting tensile strength, and flexural strength, providing theoretical support for the study of high-temperature performance of RC.