Studies on capture sizes and catch in fishing season of brooders of mitten crab in estuary of the Changjiang River were carried out during 1997-2005, and at the same time current resource and MSY were estimated. Mean values of carapace length, width and body weight were 61mm, 66mm and 142g respectively, and the proportion between female and male was 1 :2.16. In the corresponding period, average yield was 2.03 tons and MSY evaluated by model of schaefer was 1.06 tons. In research time, yield fluctuated exquisitely and catch percentage of November rose evidently. Besides, exorbitant differences of capture sizes in individuals and irregular fluctuation of correlative factors could also be found. To protect resource of mitten crab, immovable net fishing should be forbidden or restricted, and more attention should be paid to control the fishing intensity around the Jiuduan alluvion. In conclusion, certain proposals are put forward. Further studies should be taken on spawning habits and trend of catch fluctuation of brooders of mitten crab in Changjiang River estuary. Integrated protect system may establish as soon as possible. At last, to strengthen management and insist on secure artificial propagation is required.