The invention discloses a blade compensation technology for an underwater two-shaft linkage dicing cutter. According to the underwater two-shaft linkage dicing cutter, in the grain-sized dicing process, a molten polymer is extruded out of a die head, and meanwhile a motor drives a transmission shaft and a connecting transition shaft through a synchronous belt; the connecting transition shaft drives a cutterhead shaft, a cutterhead and a blade to make coaxial high-speed rotation through a connecting shaft slider, and the blade corresponds to a discharging outlet to perform rotary cutting on extrusion water cooling forming raw materials; the blade rotates at a high speed for cutting, and meanwhile an axial pushing device drives an axial pushing shaft to make axial displacement under the telescoping action of a piston rod; and axial displacement force of the axial pushing shaft is sequentially transmitted to the cutterhead shaft, the cutterhead and the blade, and thus the rotating surface of the blade and the discharging outlet of the die head are flatly attached for rotary cutting. By means of the blade compensation technology, power and mechanism cutting are set separately and are connected through the synchronous belt; axial telescoping can be achieved through the piston rod, and abrasion of the blade and the die head can be compensated for in time; and the failure rate is reduced, maintenance is made convenient, and the service life is prolonged.