Aiming at the problems of manual coal extraction, large number of workers, high working intensity, low construction efficiency, and the need to destroy the original roadway support, resulting in waste of materials and inconsistency between the silo roof support and the roadway roof support, when the water bin excavation is carried out by gun excavation after roadway excavation. By improving the technology of water chamber excavation and supporting parameters of water chamber, simultaneous excavation of water chamber at the same time of roadway excavation effectively reduces workers, reduces labor intensity and improves construction efficiency. Compared with the original technology, the construction efficiency can be increased by 33.3%. Moreover, the supporting materials of water chamber roof, bolt, anchor cable row spacing and roadway support materials are consistent, which ensures the support system of roadway and chamber.