Nanosized Y2Sn2O7 powder photocatalysts with different particle sizes were synthesized through the low temperature hydrothermal method by using different organic agents. The samples were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), surface area and porosity analyzer, and ultraviolet-visible (UV-vis) spectroscopes. Photocatalytic measurements showed Y2Sn2O7 nanocrystals with about 10nm particle sizes possess superior photocatalytic properties in water purification and may find potential application in related fields. (c) 2006 Elsevier B.V. All rights reserved.