Abstract: To solve the problems such as the blind arrangement of borehole spacing based on experi⁃ ence during the gas drainage along the coal seam in the underground mine of Lu 'an Chemical No.5 Mine， which affects the gas drainage effect，combined with the actual situation of the 10111 transportation roadway underground in the mine，a gas drainage model was established，and the variation of gas pressure under dif⁃ ferent hole spacing distributions was analyzed. The influence of the superimposed effect of porous extraction was verified. Through the research on the pressure distribution under the same spacing and the superim⁃ posed influence of extraction under different spacings，the correlation between the hole spacing that meets the practical application and the extraction radius of a single hole was determined for the first time，laying the foundation for the scientific and reasonable design of underground gas extraction parameters. Practical applications show that the larger the borehole spacing，the smaller the superimposed influence of extraction at different boreholes. Taking the 10111 transportation roadway as the engineering verification object，it is determined that the design is carried out according to the 120 d pre-extraction period. The effective extrac⁃ tion radius of the boreholes is 2 200 mm，and the optimal layout spacing of the boreholes is 6 000 mm. The accuracy of the relationship between the borehole spacing and the extraction radius of a single hole was veri⁃ fied，laying a foundation for improving the effect of underground gas control and enhancing the safety of un⁃ derground operations.

Key words: gas extraction, hole spacing, extraction superposition, extraction radius