The invention provides a portable raman spectrometer based on spectral analysis of a micro electro mechanical system. On the basis of the micro electro mechanical system, the portable raman spectrometer comprises a laser light source, a raman probe head and a spectrum detection system of a spectrograph, wherein the laser light source comprises a semiconductor laser which is used for generating lasers, the power of the generated lasers is not less than 200 milliwatts, and the line width of the generated lasers is not greater than 0.2 nanometers; the raman probe head comprises a laser outputting optical path and a raman scattered light collecting optical path which does not comprise a light filter for filtering rayleigh scattered light; and the spectrograph comprises the spectrum detection system which sequentially consists of a focusing lens I, a digital micromirror device (DMD) module I, a collimating lens, a chromatic dispersion optical grid, a focusing lens II, a digital micromirror device (DMD) module II, a de-chromatic dispersion optical grid, a focusing lens III, a single-point detector and a signal processor. The portable raman spectrometer has the advantages of being capable of keeping the resolution ratio of spectrum detection and improving the sensitivity of spectrum detection, being suitable for detection on weak signals such as raman signals, and the like.