Abstract: The article studied increasing yield and population dynamics of azolla in rice-duck-azolla integrated farming. The results showed that it improves rice yield and rice quality, because of food chain complexity and system stability in rice-duck-azolla integrated farming. Ducks’ activity make for azolla growth, and decreasing speed of azolla is lower than rice-azolla treatment. The amount of ducks eating azolla is 40.8kg in total integrated period. In a word, rice-duck-azolla integrated farming is a safe and high efficiently ecological approach.