Abstract: Water environment stress has been increasing in Taihu Lake Watershed due to rapid economic development and population growth. The evaluation index system of water environmental carrying capacity （WECC） in Taihu Lake Watershed was constructed from three aspects of water resource， water pollution and social economy， according to the current situation. The logarithmic function model was selected as a carrying degree model for the single indicator， and the weights of each index contributing to their parent indicators were determined using analytic hierarchy process （AHP）. Based on the data from the statistic yearbooks， WECC of Taihu Lake Watershed from 1992 to 2011 was evaluated. The results showed that the key indices in WECC were Engel coefficient of city residents， recycling rate of water used by industries and per capita net income of farmers. The WECC in Taihu Lake Watershed has been increasing during last 20 years， and the status of water environment has changed from fragile in 1992 to normal in 2011. The improvement of water environment might be attributed to the increasing capacity in water pollution subsystem and social economy subsystem. Finally， corresponding policy recommendations to maintain and enhance the WECC of Taihu Lake Watershed were discussed according to the results.

Key words: Taihu Lake Watershed, water environmental carrying capacity, analytic hierarchy process, dynamic assessment