The invention discloses a two-stage arc plasma torch, and relates to a plasma device. The two-stage arc plasma torch is composed of a back base, a first cathode, a first insulating torch frame, a first anode, a second cathode, a first pipe sleeve, a second insulating torch frame, a second anode and a second pipe sleeve, wherein the first cathode is installed in an installing spiral opening in the front end of the center of a rotating body of the back base, the second cathode is connected to the front end of the first anode, the first anode and the second cathode are embedded in the first pipe sleeve, the second anode is embedded in the second pipe sleeve, the back base and the first cathode are installed in a rear installing groove of the first insulating torch frame, the first pipe sleeve, the first anode and the second cathode are installed in a front installing groove of the first insulating torch frame and a rear connecting groove opening of the second insulating torch frame, and the second pipe sleeve and the second anode are installed in a front connecting groove opening of the second insulating torch frame (6). Two-stage high-temperature plasma arcs are generated in the plasma torch, the plasma torch can reach a higher processing temperature, and the heating efficiency and the decomposition capacity of the plasma torch are improved.