ing at the problem that it is difficult for micro-spectrometer to take into account both spectral resolution and spectral range, a design method of cascade Fabry-Perot interferometer and micro curved grating spectrometer is proposed in this paper. The matching conditions of the two spectrometers and the spectral characteristics of the cascade optical systems are analyzed, and a spectral data reconstruction algorithm is proposed. A laser Raman spectrometer is designed with ZEMAX software. The spectrometer has a size of 25 mm×6 mm×6 mm, a numerical aperture of 0.22, a Raman spectrum range of 150-3200 cm ^-1, and a spectral resolution of about 6 cm ^-1. The scanning process of the standard Raman spectrum signal is simulated, and the spectral signal is sampled with a 2.4 mm long linear array detector. The resolution of the reconstructed Raman spectrum is about 6.4 cm ^-1, and the deviation from the standard Raman spectrum is 0.4 cm ^-1. The feasibility of the design method and reconstruction algorithm are verified. At the same time, the spectrometer can be miniaturized and the cost can be reduced based on micro-electro-mechanical system technology, which can meet the application requirements of hand-held, portable spectral detection and industrial on-line spectral detection, and has high practical application value.