Abstract: Nano-sized Cu2O was prepared by slow-releasing technology using Cu（NO3）2 as raw material，ethylenediamine and NaOH as complexants，and glucose as reducing agent.Sample was characterized by means of XRD and SEM.Photocatalytic degradation of methylene blue in aqueous solution was used as a probe reaction to evaluate photocatalytic activity of nano-sized Cu2O.Results showed that the Cu2O powder with average particle size of about 29 nm could be prepared when the concentration of Cu（NO3）2 was 0.35 mol/L and amount-of-substance ratio of Cu（NO3）2 to C6H12O6  was 1∶0.54；when the addition amount of Cu2O was 0.4 g/L，photocatalytic degradation rate of methylene blue can reach to 100%.

Key words: nano-sized Cu2O, slow-releasing technology, photocatalytic degradation, methylene blue