Abstract: Abstract: Coal gangue is the solid waste from coal mining. Because of weathering, the physico-chemical properties of the coal gangue exposed on the ground's surface changes constantly. In order to study the change of coal gangue physico-chemical properties under the effects of weathering, the electrical conductivity, pH value and cation exchange capacity, 3 major physico-chemical indices are chosen to analyze their change characteristics and general regularities with the weathering time and the buried depth of coal gangue. The research chooses the distributing area of coal gangue with different weathering age, and divides the research layer into upper layer and lower layer, which are from surface to 30 cm depth and from 30 to 60 cm depth, respectively. A total of 135 samples from 5 coal gangue hills with different weathering age in Panbei, Panyi as well as Xinzhuangzi coal mines in Huainan mining area are collected with the stratified sampling method. The results show that there are certain change regularities of the physico-chemical properties of the coal gangue. The electrical conductivity and pH value of coal gangue decrease with the increasing of weathering age. And the cation exchange capacity increases along with the increasing of weathering age. The 3 indices of fresh coal gangue have a faster decrease rate within the early 2 a. The electrical conductivity reduces by 30% and the pH value falls by nearly 10% within the early 2 a. Then they change slowly. The cation exchange capacity can be increased by 17% within the early 2 a, and then its change grows slower. The change characteristics of physico-chemical properties of the coal gangue in profile are also obvious. Through the comparative analysis of the upper and lower layers, it is found that the electric conductivity and pH value in the upper layer are generally slightly higher than that of the lower layer, while the cation exchange capacity in the upper layer is slightly lower than that of the lower layer. The difference of pH value between the 2 layers is only from 0.1 to 0.3. The spatial and temporal variations of coal gangue conductivity, pH value and cation exchange capacity are all closely related to the weathering time or the degree of weathering. The great change occurs in the physico-chemical properties of coal gangue exposed to the ground's surface within 2 a. It shows that the weathering is significant. Of course, the temperature effect and hydrolysis as well as other physical processes play the role in the process. Lumpiness decrease of coal gangue due to physical weathering can speed up the change of chemical and other physical indicators. From the angle of the mining area land reclamation, these changes of the physical and chemical properties of coal gangue will be in favor of land reclamation in the mining area. The results provide the theoretical basis for land reclamation of coal gangue storage area.