Taking 6124 working face in ultrathick coal seam of Haishiwan coal mine as the research object, in order to determine the influence of upper protective layer mining on 6124 working face in lower ultrathick coal seam, the numerical simulation study on the change laws of stress and displacement of the protected layer after the upper protective layer mining was carried out by using FLAC3D software. The results showed that the displacement of the protected area in the protected layer presented the archshape distribution in the vertical direction, the change of the maximum displacement of the protective layer was 354 mm, and the change range was between 160-354 mm. The stress change of the protected area in the protected layer presented the Vshape distribution, the change of the maximum tensile stress of the protective layer was 0.489 MPa, and the change range was between 0.314-0.489 MPa. The change of the maximum pressure stress was 31.3 MPa, and the change range was between 25.8-31.3 MPa. After the implementation of upper protective layer mining, the gas extraction rate of coal seam increased by 39.5%, the residual gas content reduced to 7.16 m3/t, and the residual gas pressure reduced to 0.58 MPa. The determination of this parameter provides certain theoretical guidance for the rational exploitation of the ultrathick coal seam containing high gas in Haishiwan coal mine.