To address the technical demands of acidizing stimulation and reinjection enhancement in carbonate reservoirs of geothermal wells, laboratory experiments were conducted to evaluate the dissolution performance of cuttings from the Shenre-1 well with various acid systems under high-temperature conditions. By analyzing the effects of acid concentration and composition at different temperatures, an optimized acid formulation suitable for carbonate reservoir characteristics was developed. Experimental results indicate that adding a certain proportion of small-molecule organic acids or depolymerized microemulsion acids to a 20% hydrochloric acid base significantly increases the total dissolution capacity and improves retardation performance. This newly formulated acid system was applied in four geothermal wells of the Renqiu project. Notably, after acidizing the Ren11-P7 well, the water production rate increased to 3600 m3, marking a 214% rise in production and a 118% improvement in reinjection capacity. Both laboratory and field results demonstrate that the acid system provides excellent deep penetration, strong acid dissolution, and significant enhancement in production and reinjection performance, offering a solid theoretical and practical foundation for carbonate reservoir acidizing in geothermal wells and showing strong potential for wider application.