Downhole drilling dustproof drainage device

The utility model discloses a dustproof drainage device for underground drilling, and particularly relates to the technical field of underground drilling equipment, the dustproof drainage device for underground drilling comprises a drilling pipe, a drainage pipe and a water inlet pipe, one end of the drilling pipe is used for extending into a drilling hole, the outer side wall of the drilling pipe extending into the drilling hole can be fixedly connected with the inner side wall of the drilling hole in a sealed mode, and the drainage pipe is used for drainage of the drilling pipe. The other end of the drilling pipe can be fixedly connected with a drilling tool stretching into the drilling pipe in a sealed mode, one end of the drainage pipe is fixedly connected and communicated with the side wall, located outside a drilling hole, of the drilling pipe, the other end of the drainage pipe is fixedly connected and communicated with the slag discharging pipe, one end of the water inlet pipe is fixedly connected and