Water pressure sealing device for through hole

The invention relates to a through hole water pressure sealing device which comprises a handle shaft, a telescopic hole clamping mechanism is arranged in the handle shaft, the periphery of the handle shaft is sequentially sleeved with a sealing ring and a gland from bottom to top, the upper portion of the handle shaft is sleeved with a handle sleeve, and a sealing gasket is arranged between the lower end of the handle sleeve and the gland in a sleeved mode. The telescopic hole clamping mechanism mounting cavity comprises a telescopic cavity and a mandrel cavity which are communicated with each other, the telescopic hole clamping mechanism comprises a mandrel, a gear and sliding blocks, the mandrel is rotationally mounted in the mandrel cavity of the telescopic hole clamping mechanism, the lower portion of the mandrel is connected with the gear, the two sliding blocks are arranged on the periphery of the gear in an array mode with the gear as the circle center, and one end of each sliding block is provided wit