Abstract: The uniaxial compression test of raw coal samples under different water immersion time 0 d, 0.6 d, 3 d(saturated),30 d, 90 d was carried out by sampling the No.4 coal seam of the 4104 working face in WenjiapoCoal Mine.The mechanical characteristic parameters such as peak stress and elastic modulus of coal samples in Wenjiapo Coal Mine under five different water immersion time were obtained, and a damage constitutive model of coal under water immersion was constructed.The results show that: Through the test of different water immersion time of 0 d, 0.6 d, 3 d(saturated),30 d and 90 d, it is confirmed that the uniaxial compressive strength and elastic modulus of coal in Wenjiapo Coal Mine increase with the increase of water immersion time, and the decrease gradually increases.It is confirmed by experiments that the coal body of No.4 coal seam in the 4104 working face of Wenjiapo Coal Mine can reach full saturation after soaking in mine water for 3 days, and the uniaxial compressive strength and elastic modulus of coal samples in full saturation state decrease more than those in non-saturation state.Based on continuous damage mechanics and Weibull statistical damage theory, a damage constitutive model of coal considering water immersion-stress is proposed, which can better reflect the influence of different water immersion time on the mechanical properties of coal.Our research is of great significance to evaluate the stability of Wenjiapo Coal Mine in its life cycle.