A quantitative model of vegetable oil adulterated with fried animal oil has been established based on near infrared reflectance (NIRS) and chemometrics. A spectroradiometer was used for collecting spectra collected in 10 000~4 000 cm^-1. The NIR spectra were collected from 100 samples. By using the TQ-Analyst, the best pretreatment method was obtained while choosing the total spectra area combined with PLS. The best pretreatment method is the first derivative combined with Norris derivative filter. The model is feasible, with the Corr. Coeff. of 0.992 0, RMSEP of 3.11, and the result of t-test is passable while the validation method is cross validation. In this paper, a feasible method is established to detect vegetable oil adulterated with fried animal oil.