Underwater pile foundation mud auxiliary device and construction method

The invention discloses an underwater pile foundation mud construction auxiliary device and a construction method. The underwater pile foundation mud construction auxiliary device comprises a pile foundation horizontal positioning mechanism, and the pile foundation horizontal positioning mechanism is provided with a steel casing formed by bending a steel plate with the thickness of 4 mm and a positioning rod installed on the steel casing; the steel casing positioning guide frame is built on the periphery of the steel casing so as to keep the position of the steel casing; the pile foundation horizontal positioning mechanism comprises two steel pile casings, namely an inner pile casing and an outer pile casing; the system positions the horizontal position of the pile foundation through the pile foundation horizontal positioning mechanism. According to the device, the mode that the double-layer steel pile casing is used for casing driving, and the inner pile casing is used for fixing and stopping water through u