Abstract: The effects of the LF-NMR instrument parameters, detection temperature and volume on the stability and reproducibility of oils' relaxometry characteristics results had been investigated with the taken soybean oil, palm oil and lard as the samples. The results indicated that good stability and reproducibility could be guaranteed if choosing the following parameters, such as TR=2000ms, τ=250μs, EchoCount=6000, and before the measurement, a sample of 2.5mL should be stabilized at 50℃. Then the method was employed to discriminate 8 solid oil samples, 10 liquid hogwash oil samples. The result indicated that the proposed methodology was a useful tool to authenticate the hogwash oils, and the correct recognition rate was 75% and100%, respectively, and the false positive rate had been effectively avoided. Meanwhile, the difference of S21 peak area could reflect the adulterated ratio, which means that. The developed method had a good possibility to be used to assess the oil quality in the future.