The invention discloses an electric speed reducer driving photovoltaic plate two-dimensional sun tracking apparatus. The apparatus comprises a speed reducer and photovoltaic plates. The chain of the speed reducer drives sprocket wheels of the multiple photovoltaic plates, the upper surfaces and the lower surfaces of the photovoltaic plates are respectively in rigid connection with an upper electromagnetic clutch output shaft and a lower electromagnetic clutch output shaft which are coaxial, the lower electromagnetic clutch output shaft is connected with a main shaft, and the upper electromagnetic clutch output shaft is connected with an elevation angle transmission device. According to the invention, a conventional transmission mechanism which is composed of two machines and one plate and is a two-dimensional transmission apparatus using one machine to drive hundreds of plates, and the cost is greatly reduced; only one wind power wind direction sensor is additionally arranged on a total controller, such that limit wind power and snow accumulation in case of a snowy day can be prevented; and a power disc is provided for a dust removing apparatus almost without any increase of the cost.