To clarify the strata movement characteristics and protection performance of protected seams during long-distance upper protective seam mining, the No. 11 outburst-prone coal seam protected by the No. 2 upper protective coal seam in Dawan Mine was selected as the research object. A numerical mining model for the upper protective seam was established utilizing the 3DEC discrete element software, and the strata movement laws induced by protective seam extraction were analyzed. A total of eight field investigation boreholes were arranged on-site, through which the variations in gas pressure, gas flow rate and permeability coefficient of the protected seam were quantitatively determined. The research results indicate that shear failure is predominantly generated in overlying strata after the excavation of the upper protective seam. The stress within the protected seam is characterized by progressive reduction, range expansion and final stabilization, and a numerical strike pressure-relief angle of 66° is obtained through numerical simulation. Meanwhile, the field measurement results demonstrate that the field strike pressure-relief angle is determined as 52°. Within the effective pressure-relief zone, the gas pressure is reduced from the initial range of 2.17～2.30 MPa to 0.11～0.17 MPa, which is lower than the coal and gas outburst critical value of 0.74 MPa, while the maximum permeability coefficient is increased to 19.75 m2/(MPa2·d). Accordingly, it is recommended that the mining activities of the protected seam should be confined within the effective protection scope corresponding to the pressure-relief angle of 52°, and the lagging distance relative to the working face of the upper protective seam should be no less than 120 m. This study can provide a theoretical basis for the engineering application of similar long-distance upper protective seam mining projects.