Well Gulong1 is the deepest natural gas exploration well of Daqing oil field in 2008, air/mist drilling practice was made in the Ф311.2 mm third spud section. According to the existing problems, analysis on the application was made for air drilling with different mediums and proper drilling method was optimally selected. The practice showed that the record was made with the deepest well depth and the highest temperature for air drilling in Ф311.2 mm well section in Daqing oil field Song-Liao basin, the air/mist drilling reached to 1196.05 m with average penetration rate of 7.9 m/h, and the maximum drilling footage was up to 552.86 m.