The invention discloses a rehydration method for sea cucumber, which comprises the following steps: placing dry sea cucumber into clear water and washing surface dust and salinity; placing sea cucumber in clean water, heating to 30-60 DEG C. by micro wave, keeping the temperature for 20-90 min, and cooling naturally; cleaning the sea cucumber internal organ and impurity, placing sea cucumber into purified water, heating to 60-95 DEG C. by microwave, and keeping the temperature for 20-40 min, cooling naturally, heating to 60-95 DEG C again, keeping the temperature for 10-30 min; finally placing sea cucumber into purified water after cooling, placing in an enclosed container for vacuum-pumping, keeping the degree of vacuum at 0.02-0.09 MP, placing the sea cucumber into -4-4 DEG C. for rehydration about 6-10 hours, and obtaining the finished product, and the invention has the advantages of short time, low temperature, less nutrition loss, large rehydration multiple, plump and complete shape and glistened color.