Abstract: In order to realize the Raman spectrum detection of high spatial resolution of remote material, a fore optical system of the common aperture remote laser Raman detection system was designed. The common aperture structure was applied in the optical system to realize the common aperture and common optical axis of the laser emission system, the Raman light collection system and the micro area imaging system. The designed optical system can focus the laser to reduce the size of the laser spot, so that the system has a better spatial resolution than the 0.125 mrad. The effective aperture of the Raman light collecting lens is 50 mm, Raman scattering light image height in coupling lens focal plane was less than 25m, space optical coupling can be directed to spectrometer with the slit width of 50m, optical fiber of 50m core diameter can also be employed for coupling this optical system and spectrometer. The system can be used for laser focusing, Raman detection and micro region imaging of long distance materials.