Abstract: As geothermal exploration and development to the deep （≥3 000 m） is an important direction and inevitable choice in the future. As the most common stimulation measure in carbonate reservoirs, acid fracturing is also increasingly applied to carbonate geothermal wells, but the application effect in deep carbonate thermal reservoirs is not good. For the deep carbonate thermal reservoirs in Xiong’an Area, multi-stage acid fracturing technology is adopted, and the multi-stage acid fracturing technology of the reservoir is optimized by optimizing the formula of fracturing fluid and acid and testing the main properties. Good stimulation effects have been achieved in the geothermal field application of DRR wells: ① The fracturing fluid fracture and acid dissolution fractures are both effective, and the diversion capacity is significantly increased. ② The effect of increasing production and transformation is significant, and the water inflow increases by 30 times. It is concluded that the research results have formed the key technology of multi-stage acid fracturing in deep carbonate thermal reservoirs, which can effectively communicate the aquifers of deep carbonate thermal reservoirs, improve the length of acid erosion fractures, increase the conductivity of thermal reservoirs, and improve the water output of geothermal wells, which provides a favorable reference for the stimulation and transformation of similar geothermal reservoirs, and has good promotion value.