Molting process of E. sinensis juveniles in laboratory and the habitat, illumination and temperature in relation to molting in an earthen pond were studied during July to August, 1993. In-termolt cycle of crabs is divided into five stages (Stage A, B, C, D, E). For individuals with body-weight of 0.5-2g, stage A lasted about 2h, stage B about 15h, and stage E about 3-6h. The number of cast integuments perm 2 from weed-growing bottom was significantly greater than that from weedless bottom. Experiment shows that all the crabs molted normally at water depth of less than 2.0m. Diel variations in molting every four hours were observed, indicating that massive molting occurred at 07:00-11:00. Analysis of covariance (water temperature as covariate) suggests that the number of cast integuments every four hours in daytime (07:00-19:00) was significantly higher than that at night (19:00-07:00) (F_1,30=13.4, P=0.0009); the changes in diel water temperature (28-35℃) did not affect molting (F_7,11= 1.99, P=0.1467). Studies also show that crabs initiate molting at water temperature of about 14℃ and molt normally until 35℃.