The utility model relates to a hydraulic assisting fishing tool. The hydraulic assisting fishing tool mainly consists of a hydraulic cylinder, a central pipe and a ball seat, wherein an upper connector is sleeved on the top of the central pipe and connected with the top of the central pipe in a sealing manner, the middle part of the central pipe is provided with an annular stepped projection, the annular stepped projection and the hydraulic cylinder form a hydraulic cavity surrounding the central pipe, a sealing part is respectively arranged above and below the hydraulic cavity, the bottom of the annular stepped projection of the central pipe is circumferentially and uniformly provided with through holes which are used as hydraulic holes, a centering block is arranged below the hydraulic cylinder, the central pipe is fixedly connected with the centering block through a pressure shearing part, the bottom of the central pipe is connected with the ball seat, and the lower part of the ball seat is provided with screw threads. The central pipe drives the tool to be lifted upwards through the hydraulic effect, so that the phenomenon that the instantaneous fishing force is high when a drilling-free plug tool inner barrel is fished can be avoided, and the fishing difficulty and fishing danger can be alleviated.