In this paper, the seepage tests of mining coal were conducted by servo‐controlled seepage apparatus. These tests consist of conventional triaxial compression seepage tests, and load and unload seepage tests. It was observed that the peak strength and corresponding axial strain of raw coal samples gradually increase with the increase of confining pressure, which conforms to the Mogi‐Coulomb strength criterion, and the internal friction angle was calculated as φ = 42.65°, and the cohesion force was c = 3.56 MPa. The ultimate strength of coal samples after load and unload test was obviously lower than that of the triaxial compression test under the same confining stress conditions, and the deviatoric stress‐permeability curves consistent with the exponential function under two stress paths. In load and unload test, the damage degree of raw coal was characterized by the permeability damage rate and the maximum permeability damage rate. The permeability of coal seam was closely related to the mining stress, it presents a nonlinearly declining as the mining stress increases, and the permeability increases nonlinearly when the mining stress was released.