Abstract: Under high geostress condition, for further research the impact of slope length changes on distribution laws of the stope abutment pressure, taking the deep mine in Huainan Mining Area as an engineering background and based on the numerical simulation software FLAC^3D and engineering practice, the evolution laws of support pressure are analyzed under the ratio that the advance distance to slope length is 0.5, 1.0, 1.5. The results show that: with the increase of the slope length, the peak value of abutment pressure is located in front of the coal wall 10 m, and the stress concentration factor is 2.7; along strike direction of stope, when the ratio of S to L is 0.5, the peak of the abutment pressure is lower than that of 360 m; along incline direction of panel, when the ratio of S to L is 1.0 and 1.5, the peak value of abutment pressure at both ends of the stope shows a trend of first increase and then decrease. Comprehensive consideration of two aspects of coal mining pressure control and disaster prevention, the optimal slope length is between 200 m and 240 m.