A Hadamard transform near-infrared spectrometer used digital micro-mirror device (DMD) is proposed and designed. A grating is used for light diffraction, a DMD is applied instead of the traditional mechanical Hadamard masks for optical modulation, and an InGaAs single point detector is used as the optical sensor. Suitable length and width of the slit, incident angle of the grating and the focal length of lens are selected by analyzing some key influential factors to the spectrometer′s performance, such as resolution, utilization ratio of light energy, volume of the system and costs. Section optimization method is used during the design of the optical system, and then the images of slit on the DMD, the size of the spot on detector are analyzed. The simulation resolution is less than 4 nm， the spot size on InGaAs single point detector is smaller than 3 mm, and the size of the optical system is 75 mm×25 mm×85 mm . In order to improve the ability in detecting teeny light signal, a light collecting structure is proposed, which can improve the utilization ratio of light energy by 24.2% theoretically. The experiment results show that the spectral resolution of the system is better than 6 nm, and the light collecting structure can significantly improve the utilization ratio of light energy. It′s obvious that the spectrometer is high-resolution, portable and lowcost, which has broad application prospects.