An echelle spectrometer with a new optical path based on a Digital Micro Device (DMD)was proposed and a new spectrum receiving method was used to reduce the cost of the grating spectrograph and the complexity of data processing. The DMD with single wavelength getting function and an one-dimensional photomultiplier (PMT) were combined to receive spectral information of the echelle spectrometer. By which, the cost of the instrument was reduced and the spectral restore algorithm for the echelle spectrometer and the scan driving algorithm for the DMD were integrated to improve algorithm efficiency. Because the fill factor of CCD is lower than that of DMD, this kind of echelle spectrometer should be giving a higher imaging quality and higher imaging energy. According to the characteristics of the echelle spectrometer and the limited range of selected optical materials, the multi-optimization method was employed to design the optical path structure parameters of the echelle spectrometers such as quasi-direct mirror, echelle grating, prism and focusing mirror. Moreover, the Czerny-TurnerC-T structure was added into the system to correct the asymmetric aberration and three correction lenses was used to correct the spherical aberration astigmatism. Finally, the resolution of the designed spectrometer system has reached 0.01 nm and the system imaging energy in one pixel can be 70%.