Porous Cu2O-Cu hollow spheres were successfully synthesized by a facile, one-pot and green method with assistance of ultrasonic technique. By prolonging ultrasonic irradiation time, the solid spheres of Cu2O transformed into core shell structure, then into hollow spheres, which accompanied with composition shift. XRD, FE-SEM, TEM, EDX and XPS were used to investigate the structural and composition transformation of the products. Finds indicated that the formation of Cu2O-Cu hollow spheres was caused by the sacrificial template-directed chemical transformation from Cu2O to Cu and the re-crystallization of Cu2O on the shell based on Ostwald ripening effect together. Furthermore, Cu2O-Cu hollow spheres with rough surface and available pores exhibited excellent adsorption ability and better photo-catalytic activity for the degradation of methyl orange compared to other structures. (C) 2014 Elsevier B.V. All rights reserved.