In this study, with the use of LF-NMR technology, IR pulse sequence and CPMG pulse sequence were applied to detect the changes in the moisture of fresh milk samples, which were stored up at 30°C for 96 hours. Relaxation time signal T1 and T2 were measured to analyze synthetically the combination and mobility of water molecules. Furthermore, T21,T22 proton density were inversed by T2 to observe the change of bound water and free water, then the total water content can be determined by superposition of inversion signals. Meanwhile, the ratio of T21 and T22 can be used for quality control and rapid detection of corruption. The experiment results demonstrate that the moisture of milk can be used to determine the quality variation of milk. This research method analyzes and summarizes the change rules of moisture combination state in fresh milk during storage. Consequently, the freshness of milk can be determined rapidly and effectively, and the results will be beneficial to the real-time quality monitoring of fresh milk.