Small molecules that exist in a gaseous state have their Raman characteristics peaks with small spectral line intrinsic broadening. Even under various gas mixing conditions, their characteristic Raman spectra overlap less, allowing for simultaneous detection and analysis of multiple components. However, the low molecular density of gases and weak Raman scattering signals limit the application of Raman technology in gas detection. This article improves the excitation efficiency of Raman spectroscopy through the design of multiple reflection optics, and increases the collection efficiency of Raman scattering signals through the design of an integrating sphere. A highly sensitive and multi-component gas simultaneous detection device is constructed, which can achieve non-contact, non-destructive, on-site, and in situ analysis, and has both qualitative and quantitative analysis functions. The detection concentration range of gas concentration is wide, and it is also suitable for the analysis of isomers and isotope substituted gas molecules, greatly expanding the application of Raman spectroscopy technology in gas detection.