The invention discloses an accelerator control device. The accelerator control device comprises a vehicle controller, an accelerator motor and an engine controller, and further comprises a signal conversion module, wherein the signal conversion module is provided with the accelerator signal converter; the input end of the accelerator signal converter is connected with the accelerator motor, and the output end of the accelerator signal converter is connected to the input end of the engine controller. The device has a signal conversion function, can effectively solve the technical problem of incompatibility of an electric control engine with a signal interface of the original vehicle control system when the electric control engine replaces a mechanical pump type engine, has the advantages of rational structure, low cost, high control precision and the like, and can be widely applied to an excavator power system with the electric control engine as the main fitting. The invention also discloses an engineering plant with the accelerator control device.