The invention relates to a cylindrical accessory machining method and system for a metal mold. The method comprises the steps that firstly, surface induction quenching pretreatment is carried out on a blank of a roughly-machined cylindrical accessory, and a hardening layer is formed on the surface of the blank; secondly, the pulse current is exerted on the blank, pulse current tempering treatment is carried out on the hardening layer on the surface of the blank, and meanwhile turning machining is carried out to form a semi-finished accessory; and thirdly, the semi-finished accessory rotates, the pulse current is further exerted on the semi-finished product, electroplastic treatment is carried out on the surface layer of the semi-finished accessory, and ultrasonic peening rolling is carried out on the surface of the semi-finished product through an ultrasonic rolling device. The system is formed through refitting on a lathe and is suitable for machining guide columns and various metal rotation body accessories through the method. Compared with a traditional technology, according to the method, the overall mechanical performance, the surface quality and the surface smoothness of the surface layers of the guide columns can be obviously improved, the production procedure is greatly simplified, the production efficiency is improved, and the production cost is reduced.