Abstract: According to exploration drilling data of the Feixianguan Formation in the east of Sichuan, this paper has researched into the accumulation condition and controlling factors of oolitic beach gas reservoir in Feixianguan Formation. The research indicates that controlling factors of oolitic beach gas reservoir here are precipitation facies, dolomitization and burial dissolution. Through the accumulation conditions of oolitic beach gas reservoirs in Feixianguan Formation, gas reservoirs are mainly structural traps and its seal conditions are well. Critical factors of oolitic beach gas reservoir's accumulation condition in Feixianguan Formation are reservoir and trap. On the base of above research, precipitation facies, diagenetic facies, profitable hydrocarbons accumulation facies, partial structure, drilled show and hydrocarbon test result, this paper has anticipated and classified beneficial area is land-tied Sichuan-carbonate tableland's fringe oolitic beach on Kaijiang-Liangping ocean trough's outer edge area and Kaijiang-Liangping ocean trough's outer edge inner margin area.