Abstract:Based on the calculation of water environmental capacity 1271 towns among the 51 most seriously affected counties in the Wenchuan Earthquake zone, Sichuan Province, the environmental suitability of different regions was assessed in order to provide a scientific reference point for the population and economy in post-Wenchuan Earthquake restoration and reconstruction. COD and NH3-N were used to assess water environmental capacity. First, the runoff amount of every unit was calculated using parameters such as rainfall, flow coefficient and runoff quantity; second, environmental capacity was estimated from the water environmental quality standards and water background quality; finally, environmental suitability was assessed based on calculation of the degree of water pollution stress. The results showed: (1) regional differences in water environmental capacity: the water capacity of villages and towns in the northern tri-province boundary region, the southeastern edge and the inner Sichuan Basin was high, while that in the western mountain area was low; (2) water pollution stress in the southwest was low and environmental suitability was high; (3) water pollution stress in the natural protection area in the western region was high and environmental suitability was low; (4) water pollution stress in areas close to the Chengdu Plain was high and the environmental suitability was low; (5) The distribution of environmental suitability level presents clear regionality as well as some dispersivity.