Abstract: According to the ecological conditions and the function of agro-ecosystem of Kai county, this article evaluated the agro-ecological environmental quality,analyzed the existing problems in agricultural ecology and put forward some measures for protecting the ecological environment.we selected soil, air and water as main factors of ecological environment which include, soil fertility, soil quality, climate resources, air quality, water resources and water quality.The productivity of farmland was selected to reflect the function of agro-ecosystem.Based on the evaluation of singal factor, we used the method of "weighting factors" for comprehensive evaluation . We quantitatively described the agro-ecological environmental quality of different agricultural areas in Kai county, and took them in order.The research results showed that the agro-ecological environmental quality in Kai county is degrading because of human activities. The differences between agricultural areas in Kai county are obvious.The agro-ecological environmental quality of I area is the best, and IV area, the worst. The disadvantages for fully development of agricultural potential included overcut, soil erosion and water loss and unreasonable agricultural structure as well as natural incoordination of water and heat.