During the processing of aquatic products, the detection of water content is a very important indicator. In this paper, by studying and analyzing the changes of water content in different aquatic products processing by low field nuclear magnetic resonance technology, it is found that it can provide information on the kinetic behavior of water molecules, the content and distribution of components, the storage process and the preservation method. Therefore, low-field nuclear magnetic resonance technology has broad application prospects in the field of aquatic product processing and research, and can provide important scientific basis for the quality control and improvement of aquatic products.