Abstract: In order to investigate the effects of specimen size and fiber volume fraction on the compressive mechanical properties of basalt fiber reinforced concrete (BFRC) at low temperatures, static cube compression tests were conducted on four specimen sizes (70, 100, 150, and 200 mm) with a fiber volume fraction of 0.0%~0.5% in the temperature of −90 ℃ to 20 ℃. The experimental results show that the cubic compressive strength of BFRC shows a linear increase trend with the decrease of temperature, showing a significant low-temperature strengthening effect, and that the addition of basalt fibers can enhance the low-temperature strengthening effect. The compressive strength of BFRC with different fiber volume fractions shows a significant fiber reinforcement effect, which increases with the increase of volume fraction. The dominant fracture mode of fibers at low temperatures changes from pull-out failure to rupture failure, which enhances the fiber reinforcement effect with the decreasing temperature. The size effect on compressive strength increases with the decreasing temperature, and the addition of basalt fibers can effectively weaken the size effect, especially at low temperatures.The results of this study can be contribute to better understanding the low-temperature mechanical properties of BFRC and provide a valuable references for the promotion and application of BFRC in engineering structures under extreme low-temperature environments.