The technology of near-infrared spectroscopic analysis is one of the most attention attracting spectroscopic analysis technologies,and is developing rapidly nowadays.The near-infrared spectroscopy instruments are developing and emerging endlessly with the advancement of science.But the current instruments including Fourier transform filters,acousto-optie tunable filter,optical multichannel analyzers(with infrared detector array),are not suitable for spectrum monitoring online economically and expediently.In this paper,a novel near-infrared spectromonitor based on MOEMS grating light modulator is introduced.It has two obvious characteristic:firstly,compact disc (CD-R or DVD-R) is used as a diffraction grating in this system,which is a new dispersive component with high resolution and low cost.Secondly,a new method that MOEMS grating light modulators(GLM) combined with a single infrared detector to detect spectrum is used,which can avoid using of expensive infrared detector array.Optics theory has been used to analysis the essential principle of this instrument.