Abstract: The potential influencing factors of storage coefficient are considered, and the elastic modulus, overlying strata stress,Poisson’s ratio and density of overlying strata are analyzed theoretically. Combined with the related prin- ciples and knowledge of elastic mechanics and seepage mechanics,as well as the fluid-solid coupling seepage mecha- nism involved in the flow of mine water,the mathematical model of storage coefficient considering the effect of effective stress is established,and the analytical solution of the model is determined. Taking Kuangou coal mine underground reservoir as an example,the storage coefficient of the reservoir is calculated and the influencing factors are analyzed. The results show that the influence of mining height on storage coefficient is the biggest,overlying strata stress is the second,and elastic modulus is the smallest. The storage coefficient decreases with the increase of overlying strata stress and height of caving zone,while it increases with the increase of Poisson’ s ratio,elastic modulus and mining height. When the elastic modulus increases by 1. 1 GPa,the increase range of storage coefficient is 0. 4% -3. 0% ;when overlying strata stress increases by 20 MPa,the decrease range of storage coefficient is 19% -39% ;when the Poisson’s ra- tio increases by 0. 1,the increase range of storage coefficient is 10% -14% ;when the height of caving zone increases by 2 m,the decrease range of storage coefficient is 8% -11% ;and when the mining height increases by 1 m,the in- crease range of storage coefficient is 20% -60% . According to the model,the distribution range of storage coefficient is 10% -35% ,which is consistent with the range of test value of drainage engineering in mining area,and the accuracy of the model is verified.