The invention discloses a manufacturing method of steel for nuclear power equipment and a forging thereof. The manufacturing method comprises the following steps: a special steel/iron material is used as a blank; a glass coating layer is coated on the surface of the blank; then, the blank is cast by adopting a compound forging mode of model forging and free forging to obtain a secondary forging blank; the secondary forging blank is normalized, is heated to 1150 DEG C by adopting a sharp-gentle-sharp gradient heating mode, and is quenched by adopting an air cooling-water cooling ternary circular alternating mode; and the steel forging for the nuclear power equipment is obtained by performing secondary tempering treatment of tempering-water cooling-tempering-water cooling on the quenched secondary forging blank. The forging process and the heat treatment process are effectively combined to prevent quenching cracking of large forgings with complicated shapes; and the manufactured steel forgings for nuclear power equipment greatly improve the comprehensive mechanical performances, the corrosion resistance and the radiation resistance, and can preferably adapt to nuclear power working condition environments.