Based on the soil erosion control project in the Three Gorges Reservoir area

42 watersheds were controlled in the first period from 1989 to 1994.The effects of the project on environmental human carrying capacity were studied in three aspects:watershed classification;environmental and human carrying capacities before and af2ter control;impact of controlling investment on environmental human carrying capacity.Results show that 42 watersheds may be divided into 6 classes.The environmental human carrying capacity had greatly increased after control in terms of dif2ferent consuming standards (food and money).The amount of rational controlling investment is about RMB ￥55

000 per square kilometer for the purpose of increasing environmental and human carrying capacity.