For problems of complex and difficulty data processing of gas emission amount in gas geological statistics method, data source of gas emission amount was analyzed, and gas emission amount database was established. Gas emission amount data was screened by percentile method, so as to find out the data which could reflect real gas emission amount rule of mine. A gas emission amount screening module was established by use of C programming language and the second development tool of CAD and applied in No.12 Coal Mine of China Pingmei Shenma Group. The application result shows that the gas emission amount screening module improves data processing speed and preparation efficiency of gas geological map and saves a lot of manpower and material resources.