Taking the double strip mining of No.4 coal seam in Dashucun Mine as the lower protective layer of No.2 coal seam, the pressure relief effect of double strip mining of lower protective layer was studied by means of numerical simulation and field monitoring. The results show that the double strip mining of No. 4 coal seam can effectively ensure the stability of coal seam, and the pressure relief range and tendency protection range of No. 2 coal seam are the largest under 70 m mining width. At this time, the expansion of No. 2 coal seam is the largest, which is 21.6 mm, accounting for 4.2‰ of coal body, and the maximum compression is 16.6 mm, accounting for 3.2‰ of coal body. The characteristics of No.2 coal seam were monitored by borehole TV, and it was found that the separated layer cracks were produced in the protected coal seam, and the gas content and gas pressure were reduced by 50 % and 60 % compared with those before mining, which verified the feasibility of the double strip mining method. The research results provide a reference for the development of coal seam gas extraction technology.