In order to clarify the rehydration characteristics dried Laminaria were suhmerged in distilled water at 200℃ for a given period of time and the rehydration value，rehydration rate and morphological changes were studied. Rehydration curves of different parts of dried Laminaria were searched by rehydration value according to the time of moisture using the theoretical model of expiession Y = AXB. The significance of the model was tested by R squared，Analysis of variance and T value
and the high correlation coeffcient was obtained. Three different parts; base， middle and top of leaf body showned three stages of rehydration rate respectively.
The rehydration rate increased rapidly for the first 10 minutes after submersion and untill. 60 minutes it increased slowly，then it approached an equilibrium. Regression line (the theoretical model is Y =A+BX) of rehydration value for rehydration
surface area of three different parts were also calculated and high correlation coeffcient was obtained between rehydration value and surface area of each part of leaf body. The increasing ratio of width was five times as much as increasing ratio of length of a given dried square Laminaria after rehydration. Morphological observation revealed that the atrophy and degeneration accompanying many vacuole of the epidermal cells of the dried Laminaria were remarkable.
Although the dried Laminaria recover its outer figure by rehydration，the fine strueture of the dried Laminaria is remarkably different from that of raw matter.