The patent abstract shows that the invention relates to the technical field of the engine, in particular discloses a redundant engine speed control device, which comprises an electronic control unit, a control unit. A crankshaft speed sensor, a second crankshaft speed sensor, a CAM speed sensor, a crankshaft signal plate and a CAM signal plate, respectively. The first crankshaft speed sensor and the second crankshaft speed sensor are used to collect the speed signal of the crankshaft signal plate; The CAM speed sensor is used to collect the speed signal and phase signal of the CAM signal plate. ECU is used according to the no. The signal status of the first crankshaft speed sensor, the second crankshaft speed sensor and the CAM speed sensor, the corresponding engine speed and phase calculation, and the output of the available engine speed and phase, according to the available engine speed and phase to determine the engine speed and phase for fuel injection control. The invention also discloses a redundant engine speed control method. The redundant engine speed control device provided by the invention is simple, reliable and has low cost.