Morphology-controlled Cu2O microcrystalline particle films had been successfully electrodeposited on tin-doped indium oxide glass substrates in CuSO4 solutions containing different amounts of polyethylene glycol (PEG) additives. With an increase of PEG, microcrystals gradually changed from irregular shapes to cubes, octahedrons, and spherical shapes. Sizes increasingly became smaller with an increase of PEG under the same deposition time. These films had been first used as recyclable photocatalysts and showed excellent and photocatalytic activities in photodegradation of methylene blue (MB) under sunlight. Activities were regularly varied relative to the morphologies of films controlled by the amount of PEG and could be further enhanced by adding a little amount of hydrogen peroxide in the MB solution. The method for controllable preparation of Cu2O microcrystals with photocatalytic activities was simple and inexpensive. The as-prepared particle films could also be used in photodegradation of many other pollutants under sunlight. (C) 2012 Elsevier Ltd. All rights reserved.