Agro-biodiversity plays important ecological functions. It is essential for global food production, livelihood security and sustainable agricultural development. Agro-biodiversity is key to the stable, healthy, productive, sustainable field ecosystem and for sustainable management of pests. It has attracted increased attention for the prevention and control of pests based on the principles and methods of systems engineering to regulate the biodiversity in agro-ecosystems. We discuss the ecological functions and mechanism of biodiversity of agro-ecosystems in preventing and controlling pests utilizing information from multiple disciplines including agricultural ecology, plant pathology, nutrition, physiology and allelopathy.