Based on on-line Raman spectrometer

using Raman spectrum and stoichiometry

combined with partial least squares（PLS）method

and experiments are carried out by a certain number of samples of aromatic hydrocarbons

build a simulation model which can quickly and precisely determine and calculate the volume fraction of each composition in the aromatic hydrocarbons samples of crude gasoline products.Experimental data show that Raman spectrum combines PLS model has character of fast analysis rate

high accuracy and well-repeatability compared with traditional detecting methods

it can replace traditional chromatography method to some extent

and has wide application in actual production.