Abstract: The formation,development and utilization of the circular economy theory and its relationships to biomass engineering and eco-agriculture are discussed.The biomass engineering,including biomass materials and energy,is an important component of eco-agriculture which is an intensive process producing biomass and jointing the biomass engineering to the circular economy.Agriculture containing the biomass engineering and circular economy can be more closely combined with the modern economy,improve the development of agricultural industry and increase the incomes of farmers.