UV Raman spectroscopy has the characteristics of high intensity Raman scattering and no fluorescence interference; visible Raman spectroscopy has the advantages of low wave number and high resolution detection. In order to combine the advantages of two excitation wavelengths, two symmetrically distributed Czerny-Turner optical paths focusing on one detector are designed for a dual-channel Raman spectrometer. Through the selection of components and calculation of the initial structure, the energy loss on the image plane can be avoided by compensating for the astigmatism in the arc-vector direction without adding extra components. Using the software Zemax, the dual-channel spectra were modeled and optimized separately, and the simultaneous detection of the spectra of 400~5000 cm^-1 (266 nm excitation) and 50~3500 cm^-1 (633 nm excitation) was finally realized. The rationality and feasibility of the design were verified by the root mean square radius, spot diagram, and modulation transfer function. The results show that the resolution of the two sets of spectrometers can reach 8 cm^-1 and 5 cm^-1, respectively. The design has the advantages of high resolution, low wave number, multi-wavelength excitation, and integration.