Abstract: A study on spermatheca of the freshwater crab,Sinopotamon yangtsekiense was performed with histologic and cytochemical metheds.Female crabs were collected from Ningguo County in Anhui Province on May 1994.The results showed that morphology of the spermatheca is associated with the ovarian cycle.During reproductive stage,a lot of mucus was secreted by the topcrine gland cells of spermathecal epithelium in lumen,providing proper fluidy medium for sperm storage,and nutrients for sperm survival.It was found that there was an obvious cytochemical changes in the epithelium and in the luminal contents of the spermatheca during different phases of the vitellogenesis cycle.