The invention discloses a dual-waveband spectral imaging system based on a digital micromirror device and an implementation method, belongs to the field of spectral imaging, and mainly relates to a microelectromechanical system technology, a spectral imaging technology and a spectral image multi-waveband fusion processing technology. The system mainly comprises a front collimating optical path composed of a target 1, a front collimating lens group 2 and a DMD 3, and two light splitting optical paths with different working wavebands. The target image is divided by n micromirror scanning units of the DMD 3 according to columns, bidirectional scanning of the target image is achieved by controlling the n micromirror scanning units to perform positive and negative deflection in sequence, then,n dispersed spectral images are obtained on detectors of the two light splitting optical paths, spectrum reconstruction is completed according to the principle that each spectral image corresponds todifferent target image units, so that the dual-waveband spectral information of the target scene is obtained. In the system, after being reflected by the DMD, the optical signals enter the two light splitting optical paths respectively, and the problems of light energy segmentation and loss caused by the beam splitter, the spectroscope and the like in the prior art are avoided. Meanwhile, the system has the advantages of being compact in system and adjustable in spatial resolution.