The invention relates to the technical field of forging, in particular to a method for forging a screw and a nut for a steam generator of a pressurized water reactor nuclear power station. The method comprises the following steps: repeatedly performing upsetting-stretching on a suitable steel ingot at the temperature of between 1,150 and 800 DEG C to ensure that the forging ratio is no less than 4; and then sequentially performing property heat treatment and machining after the heat treatment on the steel ingot to obtain the screw and the nut. The method has the advantages that: performance indexes of the screw and the nut meet the requirements of a RCC-M standard; using requirements of the screw and the nut for the steam generator of the pressurized water reactor nuclear power station are met; the safety and the reliability of the screw and the nut are greatly improved, and technical requirements of the products are met.