Acid fracturing is a stimulation method in carbonates, in which the acid is injected into a hydraulically created fracture. The encapsulating/coating acid proposed in this paper can realize deep penetrating acid fracturing, increase the effective action distance of acid solution, and improve the flow conductivity at the far end of fractures. For this purpose, a solid acid encapsulating/coating material is proposed, which maintains its structural integrity and isolates the solid acid at higher H+ ion concentrations and lower temperatures. The solid acid is released at lower H+ concentrations and higher temperatures due to the fracture of the encapsulating material. Thus, the acid release process is dually controlled by the concentration of hydrogen ions and temperature. The molecular structure, characteristic viscosity, and solubility of the encapsulating material were experimentally determined, as well as the effective content, release performance, corrosion performance, and dissolution performance. The encapsulating material was found to be composed of acrylamide and other polymers, belonging to the high polymer group. Its characteristic viscosity was approximately 2.445 dL/g, making it mainly insoluble in a high-concentration acid (>16%). The effective content of the encapsulating acid reached 85%, the critical release concentration of hydrochloric acid was about 14%, and the critical release temperature was about 95 degrees C (for hydrochloric acid concentration not exceeding 14%). Its corrosion performance was somewhat better than that of hydrochloric acid of the same concentration. The encapsulating/coating acid proposed in this paper has promising application prospects in the acid fracturing reconstruction of high temperature deep carbonate reservoirs.