Anodonta woodiana is a filter-feeding bivalve species, which lives in shallow river beds in China.Since the fishery of the species has become an important economic resource in South China, it is interesting to know its physiological budgets of carbon and nitrogen.Physiological parameters related to the acquisition and utilization of carbon and nitrogen, including oxygen consumption rate, rates of ingestion, excretion, egestion, were measured to establish the elementary budget and conversion/growth efficiencies of carbon and nitrogen of A.woodiana fed with cyanobacteria Microcystis flosaquae.A.woodiana absorbed organic particles by filtration; carbon of respiration accounted more; carbon and nitrogen of egestion were approximate to carbon of respiration; little carbon and nitrogen was excreted to external, and the rest composed the tissue by growth or gonadal development.The equation of the carbon budget ofA.woodiana indicated rates of growth, egestion, respiration and excretion in carbon composed37.65%, 35.67%, 26.61% and< 1% of ingestion rate in carbon, respectively.The equation of the nitrogen budget indicated rates of growth, egestion and excretion in nitrogen composed 55.45%, 43.18% and <2%of ingestion rate in nitrogen, respectively.It was found that every component in nitrogen budgetaccounted for similar proportion to that in carbon budget.Gross growth efficiency (K1) and net growth efficiency (K2) of nitrogen were both higher than those of carbon.Rates of ingestion and excretion in carbon of A.woodiana were greater than those in nitrogen, but the efficiency for growth of carbon is less than those of nitrogen.Overall, this study advances the understanding of two approaches to measure the carrying capacity, carbon budget and nitrogen budget and restrictive mechanisms of carbon and nitrogen toward Microcystis by A.woodiana before the outbreak of water bloom.