The invention provides a rivet removing tool and method. No special tool for removing skew rivets is available at present, rivet heads are removed with a sledge hammer by workers through a self-made tool, then rivet rods are ejected out by means of a sharp tool, the risk is extremely high, and a large number of industrial accidents are caused. A hydraulic station of a field riveting machine is used for supplying power to the rivet removing tool, and the rivet removing tool comprises a removing knife, a fixing sleeve, a positioning sliding block, a movable rivet head, a guide washer, a fixed rivet mold, a fixed rivet head and a spring. The removing knife is clamped in the positioning sliding block and makes contact with a rod of a rivet. The fixed rivet head is fixed to the other end of a rivet clamp. The fixed rivet mold is used for fixing a cap of the rivet. The rod of the rivet is removed out of an inner cavity of the fixed rivet head by applying force through a hydraulic piston rod and then taken out after being clamped. The removing knife is made of a high-strength high-plasticity material and can meet the requirements for hardness and the like, and thus the effect that the rivet removing tool is prevented from being broken in the use process is guaranteed. By the adoption of the rivet removing tool, the effect is quite remarkable, and skew rivets and redundant rivets can be removed rapidly and conveniently.