The levels of calcium and phosphorus in the muscles , hepatopancreas, carapace and cast exuviae of Chinese mitten crab, Eriocheir sinensis, were determined during the intermoult and 24h, 48h and 96h of postmoult respectively. The concentrations of calcium in the muscle in postmoult were lower than that of intermoult , but showed slight increase from 24h to 48h in postmoult. No significant changes of calcium levels were found in the hepatopancreas while the levels of calcium in the carapace increased f rom 24h to 96h in postmoult. The calcification of the carapace was almost finished after 96h of moulting. The levels of muscle phosphorus in postmoult were higher than that of intermoult , but there were no changes in the later times. The content of phosphorus increased in the hepatopancreas and decreased in the carapace in postmoult stages. The muscle calcium and phosphorus ratio decreased sharply in postmoult as compared with that of the intermoult, while it showed no changes in intermoult and 24 h of postmoult in hepatopancreas, but decreased from 24 h to 96 h of postmoult . The carapace calcium and phosphorus ratio was low in intermoult and 24 h of postmoult, but increased f rom 24 h of postmoult to 96 h. The carapace mineralization rates of calcium of Chinese mitten crab were found faster than that of phosphorus.