Abstract: During the mining period of the 30103 working face in Pingquan Coal Mine，gas exceeding the limit occurred multiple times in the upper corner，with the maximum gas exceeding the limit concentra⁃ tion reaching 2.1%，seriously threatening the safe and efficient mining of the working face. Through techni⁃ cal research，it has been determined that the main reasons for gas exceeding the limit in the upper corner in⁃ clude air leakage in the goaf，air pockets in the upper corner，and geological structural influences. Based on the current situation of gas control in the early stage of mining，the ventilation system of the working face was optimized by adopting a Y-shaped ventilation system and arranging "buried pipes in the goaf+high-lev⁃ el boreholes" for gas extraction. L - shaped air barriers and air flow ejectors were installed to reduce end air leakage and prevent tile accumulation in the upper corner，and the arrangement of boreholes along the groove was optimized. The actual application effect shows that after optimizing the ventilation system and ex⁃ traction process，the average gas concentration in the upper corner is 0.4%，the maximum gas concentration in the goaf is 1.2%，and the maximum gas concentration at the coal drop point is 0.6%. The gas concentra⁃ tion at each point is controlled within the allowable range，which solves the technical problem of corner air entrapment in traditional U-shaped ventilation systems and achieves significant application results.

Key words: fully mechanized mining face, upper corner, gas control, Y-shaped ventilation