The utility model relates to an eccentric torque adjusting device of a vibration hammer, which comprises an adjusting cylinder, an input gear, a long round barrel, a bush, a big spline sleeve, a thrust bearing, an output gear, a blocking sleeve, an adjusting shaft, spline sleeves, a stopping sleeve and a stopping rod, wherein one end of the adjusting cylinder is arranged in the hole of the long round barrel, and the other end of the adjusting cylinder is fixedly arranged in the hole of a right communication cover. The adjusting cylinder also comprises the stopping sleeve and the stopping rod, wherein the stopping sleeve is arranged at one end of a piston rod, the stopping rod (17) is arranged in the stopping sleeve to enable the stopping rod and the piston rod to axially displace instead of rotating, the other end of the adjusting cylinder is connected with the one end of an adjusting shaft through a bearing seat, the thrust bearing and an external bearing seat, and the periphery of the adjusting shaft is provided with two sections of a large rectangular spiral external spline and a small rectangular spiral external spline which are opposite at rotation direction and are respectively provided with a large spline sleeve and a spline sleeve. The device can stop the piston rod to rotate with the adjusting shaft, prolongs the service life of a cylinder O-shaped sealing ring and a skeleton oil seal, and ensures the normal work of the vibration hammer.