Abstract: Stichopus japonicus can produce an autolysis enzyme with the strongly ability of autolysis.The changes of the moisture state during the process of autolysis in stichopus japonicus were studied by the LF-NMR and drying method in the paper.The results showed that the stichopus japonicus without seawater could be autolyzed and presented water-shaped.The moisture content of it increased from 90.60% to 94.60% during autolysis process.The results of LF-NMR indicated that there were three kinds of different liquidity water including combined water ( T21, 0ms < T21< 15ms) , uneasy free water ( T22, 16ms <T22< 160ms) and free water ( T23, 300ms <T23< 620ms) .The T23of sea cucumber in the process of autolysis increased from 92.60% to 99.14% due to the evaporation of water, subsequently slowly decreased to 95.38%.The T21dwindled from the beginning of the peak ratio of 0.12% to 0.01%while the T22presented wave-shaped and irregular during the whole autolysis process.