The invention discloses a multiple-grating monochrometer. The monochrometer mainly comprises a mono-light optical splitting system, a control system, a computer and a printer, wherein the splitting system and the control system are designed as one, the upper part of the device is a grating chamber, the lower part is a controller chamber; the grating chamber mainly comprises an entrance slit, two exit slits, a color filter group, two concave mirrors, a grating turntable, a reflector and a stepper motor, wherein the open or close size of the entrance and exit slits are controlled manually; the hardware circuit adopts a second-order Butterworth filter to perform anti-aliasing filtering, and the hardware 8-bit pulse width modulation method is used to realize the control of the stepper motor. The multiple-grating monochrometer overcomes the bottleneck of low data transmission speed caused by the use of the RS232 interface before and the USB2.0 interface is used to connect with the computer. A power distribution system, a grating turntable control system, a filtering wheel control system, a reflector control system and a high speed and high accuracy data acquisition system are integrated to increase the integration degree, reliability, control precision and scanning precision of the system. The newly provided automatic scanning multiple-grating monochromatic spectrometer system has wide development prospect.