Abstract: Current research state and trend of biodiversity and its relationships with stability were briefly reviewed in the paper. Based on some cases of agroecosystems that rationally utilized biodiversity,mechanism of biodiversity in improving agroecosystem properties and efficiency were analyzed. These were: biodiversity expanded the spatial and trophic or functional niche of agroecosystems; strengthened the biological complementarity through its effects on habitat environment or trophic relationships; directly or indirectly improved the micro climate and soil environment; and promoted biological recycling of nutrients. The necessity and significance of strengthening researches on agroecosystem biodiversity, especially the current state of biodiversity of various agroecosystems; effects of management measures on biodiversity; transfer and dynamic changes of biodiversity among neighboring agroecosystems and the theory and methodology of agroecosystem biodiversity,were then explored.

Key words: maize, leaf area index, optimum field observation data.