Abstract: The application test of air foam flush drilling was carried out by the 115th Exploration Team of Shanxi Coal Geology Bureau in Weijiagou and Tongxin prospecting areas, Datong （Continued from inside back cover）coal field. W-10/60 and TYH-10/7 air compressors, and other equipments and materials were used in this test. 59 bore-holes were completed with this method and the maximum depth of hole is 601. 10 m. The results of the application test show that this method is suitable to water lack areas, seriously leak areas and worked-out areas. As compared with the mud fluid flush drilling, the air foam flush drilling made the efficiency of rigmonth increasing 90% and the cost of drilling decreasing 30%.