High-temperature gas-cooled reactors, as highly regarded fourth-generation reactors, extensively utilize graphite materials as structural material and neutron moderator. The performance of graphite has significant implications for the design, operation, and maintenance of the reactor. In this study, the friction coefficient of graphite materials was experimented in helium and nitrogen atmospheres at temperature ranges of 100 to 1300 ℃ using an independently developed graphite friction coefficient test device. The graphite friction coefficient under a helium atmosphere presents an initial increase followed by a decrease with rising temperature, reaching a maximum value of 0.174 at 200 ℃. While the friction coefficient gradually stabilized and fluctuated within the range of 0.045 to 0.056 at 400 to 900 ℃, and the friction coefficient slightly increased to 0.077 as the temperature increased over 1000 ℃. In nitrogen atmosphere, the variation trend of graphite friction coefficient was similar to that in helium atmosphere. Below 200 ℃, the graphite friction coefficient in nitrogen atmosphere exceeded that in helium atmosphere, while the peak value occurs at 100 ℃, measuring 0.196. Above 300 ℃, the friction coefficient in nitrogen atmosphere was basically consistent with that in helium atmosphere, which fluctuate within the range of 0.038 to 0.072.