Abstract: A buffer unit for the slewing platform of the tamping machine, comprising a slewing plafform, a slewing bearing and a chassis, the upper end of the said slewing bearing connects to the slewing plafform and the lower end of said slewing bearing connects to the chassis, the slewing platform can revolve around the chassis 360 degrees, further comprising a annular supporting slab, a hydraulic cylinder and a connecting rod, the annular supporting slab is fixed on the chassis by bolt. The hydraulic cylinder is fitted on the rear end of the central plane of the slewing platform, the piston rod head of the hydraulic cylinder connects to said connecting rod. The connecting rod can touch and support the annular base slab at any point of the direction of 360 degrees rotation when the hydraulic cylinder extends.