Abstract: The adulterated milk samples were tested by the CPMG sequence of the low field-nuclear magnetic resonance. In order to search for a method to analyze and process the sample data rapidly and effectively, principal component analysis (PCA) was used to monitor milk quality. Milk samples adulterated with water, salt, urea or soybean milk, reconstituted milk and pure milk were prepared for the LF-NMR testing and evaluation. The results showed that LF-NMR can be used to distinguish between pure milk and different kinds of adulterated milk. Pure milk, reconstituted milk and their mixed milk were an effective identification. There was effective identification among pure milk, reconstituted milk and their mixed milk. The application of LF-NMR in adulterated milk with different additive proportions showed the similar result, too. The PCA method can be used to analyze and process the test data of LF-NMR. LF-NMR coupled with PCA shows a greater potential in the evaluation of dairy products quality.