Abstract: Supercritical CO₂ (scCO₂) reaction may lead to dynamic changes in the material composition, accumulation and seepage conditions of shale. However, there are few reports on the water-rock reaction characterized by corrosion/precipitation and its influence regularities. Based on the use of high-pressure hydrothermal reaction experimental device and a series of characterization tests, the paper analyzes the changes of shale in chemical composition, mineral composition, surface morphology and pore structure during scCO₂-water-shale reaction, revealing the regularities of mineral corrosion, ion dissolution and precipitation in shale under CO₂ sequestration conditions. The results show that in the short-term reaction process, shale primarily exhibits corrosion characteristics, with changes in the internal calcite morphology and the development of secondary corrosion pores. In the long-term reaction process, corrosion is still dominant in shale, accompanied with occasional carbonate precipitation in partial areas. The corrosion process is mainly controlled by the development conditions of calcite, and calcite corrosion leads to an increase in the pore volume and specific surface area of shale. The precipitation process is affected by clay minerals represented by illite and illite/smectite mixed layers, and an increase in both contents can lead to the formation of more carbonate precipitates. In general, scCO₂-water-shale reaction exhibits a geochemical behavior that predominated by corrosion and supplemented by precipitation. Under the effect of corrosion or precipitation, the sequestration space in shale presents a positive incremental evolution. The calcite corrosion helps improve hydrocarbon sequestration capability in shale. Clay minerals can provide essential cations for CO₂ mineralization. The investigation on the corrosion/precipitation characteristics of shale during CO₂ sequestration can help understand the geochemical regularities of minerals and fluids under CO₂ sequestration conditions, which is of great reference value for revealing the CO₂ geo-sequestration mechanism of shale and developing the enhanced shale gas recovery techniques.