Porous Cu(2)O nanospheres with controllable structures were successfully synthesized by using ascorbic acid as the reducing agent and beta-cyclodextrin (beta-CD) as the capping agent via a sonochemical route, which was proved to be a green and convenient method for the controlled synthesis of porous Cu(2)O nanospheres. The crystal phase of the product was determined by the concentration of ascorbic acid, whereas its final structure was controlled by the ultrasonic irradiation time and the concentration of beta-CD. Moreover, porous Cu(2)O nanospheres exhibited enhanced photocatalytic activity compared with solid ones.