Designed system of coupling laser plasma emission light into optical fiber can improve efficiency of coupling plasma emission light into optical fiber and decrease system size simultaneously, which can provide hardware basis for the application of laser induced breakdown spectroscopy (LIBS) to fast, field, in-situ material composition analysis. The coupling system consists of three lenses. The first single lens is used to collimate the light emitted from plasma and the reversed telephoto consisting of the other two lenses is used to couple the collimated light into optical fiber. Coupling efficiencies of the system are all above 92% at the analysis wavelengths of Pb, Cu, Ni, Cr and Cd. The diameter of the system aperture is less than 6mm and the total length of the system is less than 30 mm. The coupling system is used to detect Cr in soil and Pb in sludge from a lead battery factory, which is compared with the methods of using double lenses collecting system and using fiber only. It is proved that the characteristic spectral lines obtained by coupling system could be more obvious and easier to recognize, limits of the detection of elements would be lower and the spectral datum could be more stable, which could be in favor of subsequent spectral lines analysis and the concentration computations of elements.