A plunger-type die locking oil cylinder of a two-plate plastic injection molding machine comprises an oil cylinder body, an oil cylinder body cover and a piston. The plunger-type die locking oil cylinder is characterized in that a Golling column is arranged in the oil cylinder body, a piston is arranged at one end of the Golling column and closely contacts with the inner wall of the oil cylinder body, and the Golling column is enabled to drive the piston to realize short-stroke piston motion in the oil cylinder body. By arranging the oil cylinder body cover on the oil cylinder and arranging the Golling column, the piston and a piston cover plate in a cavity of the oil cylinder body, the piston is enabled to be driven by the Golling column to be in short-stroke piston running in the oil cylinder body and the oil cylinder body cover, so that the problem of high energy consumption of the piston in a long-stroke oil cylinder is solved; by forming grooves in the oil cylinder body, the oil cylinder body cover and the piston and arranging a sealing member on each groove, the oil cylinder body is enabled to form a sealed structure. In addition, the plunger-type die locking oil cylinder has the advantages of simple and reasonable structure, low cost, high accuracy, high reliability and the like.