Abstract: According to the relevant provisions of "Coal Mine Gas Grade Appraisal Interim Measures" and the actual situation of the gas grade appraisement in these years, the paper discusses the existing problems in the process of gas grade appraisement, such as the selection of instruments, the selection of time, the measuring points disposition, the identification of high carbon dioxide mine, carbon dioxide concentration determination and gas drainage quantity calculation, and the paper also proposes imprvement countermeasures and suggestions.