The drilling efficiency of air DTH hammer drilling technology is 10 to 20 times higher than that of conventional drilling technology， which is of great significance for improving mineral resource exploration and development efficiency， and promoting the economic development of Guizhou Province. The southwest （Guizhou） karst area is the largest karst continuous area in the world， where carbonate strata is widely distributed， and karst caves， dissolution fissures and fractures are developed. When drilling with air DTH hammer drilling technology， air leakage is prone to occur， which leads to difficulty in return of cuttings， and even bit sticking and burial accidents. Though the partial reverse circulation drilling process with dual-wall drill rods and the air DTH hammer can effectively solve the difficulty in application of the air DTH hammer drilling process in the Karst area， but the existing sealing device is prone to wear， which limits the application of the process in deep well drilling. With the sealing device for partial reverse circulation drilling with the dual-wall drill rod and the air DTH hammer as the subject of study， through adjusting the structure of the sealing device and improving the rotation performance of the sealing ring， modification and optimization is conducted of the sealing ring to extend the service life of the sealing tool so that local reverse circulation drilling with the dual-wall drill rod and the air DTH hammer can be applied in deep well drilling.