The reproductive period of Procambarus clarkii in Wuhan area was investigated to provide basic data for developing artificial reproduction technique.The asynchronism of oogenesis was observed in the sections of ovaries.The mature eggs appeared in the sections of the ovaries sampled in two periods.One period was from April to May,and the other one was from September to October.The large eggs contained abundant yolk granules.From June to July and in November,more previtellogenic and initial vitellogenic oocytes were observed in the ovaries,although there were a few eggs in degeneration,indicating that these periods might oogenesis recovery periods after spawning.In crayfish testis,the proportion of the testicular tubules containing spermatids and sperm increased dramatically in two periods,April to June and September to October,although spermatocytes were also observed during these two periods.Furthermore,the vas deferens containing spermatozoa were frequently observed in these two periods.The ratio of the testicular tubules containing the spermatogonia and spermatocytes was higher in other periods.These results suggest that P.clarkii have two periods of reproductive peak in Wuhan area,from April to May and from September to October.