The invention discloses a spheroidizing annealing method for a shaft steel, wherein the shaft steel is heated to not less than 684 DEG C, the heat preservation time is calculated according to the effective section thickness of 3.3-4.3mm/min; the steel shaft is quickly cooled to not greater than 200 DEG C; and then the shaft stell is heated to 680-650 DEG C and the temperature is kept for 6-20h; finally, the shaft sheel is cooled slowly with the furnace. By controlling the cooling and temperature speed, the method changes the distribution of carbide particles in the steel after spheroidization,so that the carbide particles are more evenly distributed in a matrix and are distributed in crystal grains, and the segregation of carbides at grain boundaries is reduced, thereby the plasticity isenhanced, and the section shrinkage rate of the product is more than or equal to 55%; another remarkable characteristic is that spheroidizing annealing can be well realized without plastic deformation.