A mixture of four substances of benzaldehyde, iso-octane, butyl acetate, acetophenone were quantitatively analyzed by mass spectrometry combined with chemometrics.The mass chromatogram data of mixture were proceeded with two methods for quantitative analysis. One is feature selection-Multiple Linear Regression (MLR) and the other is full spectrum- Partial Least Squares (PLS). The results show that the RMSEP of benzaldehyde were 0.062　and 0.091 after selecting m/z spectrum and full spectrum respectively; RMSEP of isooctane were 0.048 and 0.057 after selecting spectrum and full spectrum respectively; which of butyl acetate were 0.021 and 0.020 and of acetophenone were 0.010 and 0.032. The feature selection results of the mixture were better than that of the full spectrum modeling results expect butyl acetate which got similar results by the two methods.