Biochar (BC) generated by pyrolysis at high temperature is a kind of porous material with great potential for carbon sequestration. The incorporation of BC into mortar as a substitute for cement can not only improve the mechanical properties of mortar, but enrich the means of carbon sequestration technology. However, the performance of concrete utilizing BC as a replacement for cement, particularly when exposed to elevated temperatures, has yet to be fully understood. Here, we provide an experimental investigation on the mechanical properties of biochar concrete (BCC) after exposure to elevated temperatures. 168 concrete specimens were poured with four different BC addition (0 %, 3 %, 5 % and 10 %) to test the mechanical strength at 7 and 28 days, and the mass loss, the residual strength, microstructures, and stress-strain curve of BCC after high temperature were obtained. The results showed that a small amount (3 %) of BC significantly improved the mechanical properties under conventional conditions. The apparent morphology of BCC after high temperature is similar to that of ordinary concrete, however, its mass loss, residual strength and peak stress have great changes. The addition of 3 % BC can increase the residual compressive strength of concrete at 300 °C, 500 °C and 700 °C by 4.8 %, 26.3 % and 25 %, respectively, compared to the BC-free one. Based on the findings, it is speculated that replacing a portion of cement with BC will be a feasible alternative to improve the performance of concrete at elevated temperature and curtail CO2 emissions that generate with the cement production.