The accuracy of coal quality test results directly determines the industrial application selection, market transaction pricing and environmental emission control effect of coal. Sampling representativeness, sample preparation standardization and scientific test conditions are the core links that affect the reliability of test data. In order to improve the standardization level of coal quality inspection, this paper takes typical coal types in China as the research object, and carries out four groups of targeted experiments : the influence of different sampling methods on the test data of steam coal, the sensitivity analysis of sample size on the ash and volatile matter of bituminous coal, the optimization of moisture determination conditions and data comparison of different coal types, and the correlation between calorific value of commercial coal and industrial analysis index. Through the system to collect experimental data, in-depth analysis of the influence mechanism of each link, clear the optimal operating parameters. The results show that mechanical sampling is more stable than manual sampling and is suitable for continuous sampling scenarios. The optimal particle size range of bituminous coal sample preparation is 0.2~0.5 mm ; the moisture determination of different coal types needs to match the differential temperature-time parameters ; the calorific value prediction model established by different coal types has higher accuracy and can meet the rapid assessment requirements of different application scenarios. The research results provide data support and technical reference for the precision and standardization of the whole process of coal quality inspection.