Based on the assessment index system of eco-agricultural construction benefit at medium scale

the assessment index system of eco-agricultural construction benefit in Changwu County was established.The weights of indicators were estimated by analytic hierarchy process(AHP).According to the data and research achievements of the evolutionary process of agricultural eco-economic system from 1980 to 2008

the comprehensive benefit of Changwu County was assessed quantitatively.Results showed that the comprehensive benefit of eco-agricultural construction was raised from "inferior" in 1980s to "good" in 2008.Development of economical benefit is most obvious

while ecological benefit develops steadily.The comprehensive benefit has been increased significantly in recent years.In conclusion

the overall function of the agricultural system should be increased by improving agro-ecological environment and ecological benefit.