Abstract As one of the main unconventional gas reservoirs, the exploration and exploitation of shale gas reservoirs has been a hot spot of global resources development. The traditional water-based fracturing fluid with the disadvantages of large water consumption and serious formation damage does not apply to shale gas reservoirs stimulation. Supercritical CO 2 fracturing technology, using harmlessness CO 2 for sand-carrying fluid, was brought forward to apply to development of shale gas reservoirs, with the advantages of no water consumption, no damage to formation, contributing to CH 4 desorption, etc. When applying supercritical CO 2 as the fracturing fluid, in fractures supercritical CO 2 interacts with shale in the presence of water. The study on the interactions of shales and supercritical CO 2 in the presence of water is a basic issues in stimulation of supercritical carbon dioxide within shale reservoirs. The objective of this study is to solve the key problems which the interactions of shale, supercritical CO 2 and water involves, such as mineral elements migration, microscopic pore structure and so on.