Abstract: In order to clarify the several air drying processes during coal sample preparation and testing, the differences between the three stages of air drying in the sample preparation process （air drying before taking the entire water sample, air drying after taking the entire water sample, and air drying after crushing） and the two air drying processes in the testing process （air drying of coal samples before general analysis and testing, air drying during the determination of external moisture in whole water samples） were analyzed from the aspects of article size and weight of the dried coal sample, drying purpose, drying method, and the state of the dried coal sample. Analyzed the effects of five stages of air drying on the moisture and temperature of coal samples. By comparing and analyzing the two air drying stages of the general analysis test coal sample, it was concluded that when the temperature and humidity conditions of the sample preparation were similar to those of the laboratory, the two air drying effects were the same, and either stage could be selected for air drying. When there was a significant difference in temperature and humidity conditions between the sample preparation room and the laboratory, air drying should be performed before the coal sample analysis, as it was conducted in the laboratory. With the continuous development of intelligent technology in coal mining and processing, it was mining and processing systems.