Abstract: It taking surface drilling gas drainage project of N2105 working face of Yuwu coal mine as an example，based on “O” ring theory of mining fracture，after numerical simulation analysis with Fluent software，combine with contrastive analysis of surface drilling gas drainage under different construction parameters，then some parameters of surface drilling position，drainage pressured of Yuwu coal mine were optimized.The studying results showed that the position in horizontal of surface drilling should arrange inside of mining fracture “O” ring，and in vertical it should be arrange between collapse zone roof to lower middle part of fracture zone，and then drainage efficiency was the highest，according orthogonality simulation contrastive analysis，the gas drainage results was the best when the distance that surface drilling hole to coal seam roof was 16m and distance to ventilation roadway was 40m，the relationship between drainage pressure and gas density present as quadratic polynomial of C=-0.013P²+1.122P-1.188，when drainage negative pressure was 45kPa，the drainage density was the highest as 25.5%，and the relationship between drainage negative pressure and gas density of gob-side entry retaining present as quadratic polynomial of C=0.0001P²-0.013P+0.637，when drainage negative pressure was 48kPa，the gad density of gob-side entry retaining was the lowest，the rationality of fitting formula was verified by practical data of drainage density and drainage negative pressure，it references for lately surface drilling parameters arrange.