Ethanol diesel as a clean fuel is a good substitute for diesel fuel. Different content of ethanol diesel oil viscosity is different, and the ethanol in the ethanol content of diesel fuel affects the quality of combustion, so we need have an instrument or method to achieve Ethanol Diesel Ingredients and Main Indicators Online Monitoring. In this paper, Savitzkv-Golay smoothing (SG), multiple scattering correction (MSC), differential processing (1stD and 2ndD), standard normal variable correction (SNV), and so on were used to calculate the original Raman spectra . The PLSR model of ethanol diesel density, viscosity and ethanol content was established by using different pretreatment methods for the original Raman spectra of different concentrations of ethanolic diesel. Compared with different pretreatment methods, the ethanol content and viscosity of PLSR model established by S-G+2ndD pretreatment has the best effect, the prediction set Rp is 0.930 and 0.918 respectively, RMSEP is 1.237 and 0.034 respectively. The PLSR model of ethanol diesel density after SG+1stD pretreatment is the best method. The optimal set of Rp is 0.962, RMSEP is 0.14×10-2. The wavelength model was selected by Recursive partial least squares(RPLS), Uninformative variables elimination(UVE), Compctitive Adaotive Reweighted Sampling(CRES), Successive Projections Algorithm (SPA) wavelength screening method after S-G+2ndD pretreatment, and the PLSR model was established. The prediction model of ethanol content of ethanol diesel oil was optimized by SPA-CARS wavelength screening method. The Rp and RMSEP were 0.978 1 and 0.825 5. The results show that the method can be used to predict the main indexes such as density, viscosity and ethanol content of ethanol diesel.