Abstract: This study aimed to investigate the effects of trypsin migration and release from the hepatopancreas of Litopenaeus vannamei on muscle water status during low-temperature storage. By injecting different concentrations of trypsin solution into the shrimp hepatopancreas and storing them under refrigeration (0 ℃) and frozen storage (-20 ℃) conditions, the content and activity of trypsin in the muscle, water content, water activity, and water migration characteristics were systematically measured using low-field nuclear magnetic resonance (LF-NMR). The results showed that under both storage conditions, the trypsin content and activity in the muscle gradually increased with higher injected trypsin concentrations and prolonged storage time, while the moisture content and water activity gradually decreased. LF-NMR analysis indicated that with increasing trypsin injection concentration and extended storage time, the peak areas of bound water (T₂₁) and immobilized water (T₂₂) decreased, while the peak area of free water (T₂₃) exhibited a fluctuating downward trend. Magnetic resonance imaging further visually confirmed that in shrimp injected with high concentrations of trypsin, muscle tissue structure was gradually disrupted during storage, and areas with high water signals showed a diffusive trend. This study enhances the theoretical understanding of shrimp quality deterioration induced by trypsin migration and degradation and provides new theoretical support for the development of quality control technologies in low-temperature stored aquatic products.