25 solutions of chlorobenzene in CCl4 with different concentrations are studied by using laser Raman spectroscopy technique. The results show the linear relationship between the Raman spectral intensity ratio of chlorobenzene and CCl4 and the concentration of chlorobenzene in 253~0.44 g/L range. The linear correlation coefficient obtained by the least square method is 0.995. Laser Raman spectroscopy technique has the advantages of rapid, nondestructive detection and no need of sample pretreatment. It is proved that this spectral measurement method is feasible for low-concentration detection and quantitative analysis of organic molecules.