Chemical stimulation can improve the fracture connectivity and permeability of an EGS reservoir. Experiments were carried out on the interaction of RMA (regular mud acid) with granite. The mechanism of acid rock action was clarified, and the dynamic model of multimineral reactions was established. Higher the HF concentration in the RMA, higher is the dissolution rate of the granite, but secondary precipitation is more likely to occur. Na+ and K+ come from feldspar and illite, Al3+ and silicon from feldspar and clay minerals, Ca2+ comes from calcite in the early stage, and is influenced by calcium- feldspar and fluorite in later stages. The reaction is a dynamic reaction under dual mechanism control. The order of magnitude of the mineral dissolution rate constant under the HF mechanism is approximately 10-4～10-5, which is increased by about 9 orders of magnitude compared to that of minerals under neutral mechanisms. The results can provide theoretical support for chemical stimulation of the EGS reservoir.