The utility model relates to a rotary joint device of a hydraulic coiling machine. The rotary joint device comprises a rotary spindle connected in a rotary joint shell; a liquid inlet hole is arranged in the rotary spindle; a liquid outlet hole is arranged on the rotary joint shell; an oil discharging groove is arranged on the rotary joint shell; the inner wall of the rotary joint shell is provided with a circulation groove for communicating the liquid inlet hole and the liquid outlet hole; a front end bearing is arranged between the front end part of the rotary joint shell and the rotary spindle; a rear end bearing is arranged between the tail end part of the rotary joint shell and the rotary spindle; a front end cover is arranged at the front end part of the rotary joint shell; a rear end cover is arranged at the tail end part of the rotary joint shell; a bearing retainer is arranged at the end part of the rear end bearing; the inner wall of the front end cover is provided with an oil seal; the inner wall of the rotary joint shell at the two sides of the circulation groove is provided with a rotating seal ring for a shaft; and a U-shaped seal groove is arranged at the end part of the rotary spindle. Compared with the prior art, the rotary joint device has the advantages that the oil leaking phenomenon is eradicated, the frictional wear between the rotary spindle and the shell is reduced, the maintenance period is shortened and the service life is prolonged.