In order to study the effect of heat treatment temperature on the gradual change law of microscopic pore evolution in coal, taking anthracite samples as an example, the pore evolution of coal at 60 ~ 150 °C heat treatment temperature was characterized by low temperature nitrogen adsorption method. The results show that the adsorption isotherms of the samples after heat treatment at four temperatures are similar to the type II adsorption isotherms. The shape of the hysteresis loop is similar to that of the H3 hysteresis loop, and the pores in the samples are mainly slit pores. With the increase of temperature, the area of isothermal hysteresis loop decreases gradually, and the connectivity of internal pore network is improved, which is beneficial to the drainage of methane in coal. The increase of temperature specific surface area plays a certain role in promoting, but it has little effect on the pore volume of anthracite samples. In addition, heat treatment has a great influence on the pore distribution characteristics of 0.5 ~ 10 nm in coal. The research results can provide some guidance for the process parameters of heat injection to increase coalbed methane production.