Mathematic model of agricultural eco-engineering is to provide the knowledge of system's present situation, function and structure. The model is also used in the forecast system for something that is about to happen and taking an additional measure to control the system for achieving the system optimization. Based on theoetic study and practice, a mathematic model of small sized agricultural eco-engineering has been established.

Taking a farmer's family in Liuminying Village of Daxing County,Beijing,as an example,the paper introduces the mathematic model of small sized agricultural eco-engineering and its application in practice.