Pure BiFeO3 (BFO) microcrystals were synthesized at the temperature as low as 120 degrees C via a urea-assisted hydrothermal process. The crystal structure, morphology and photocatalytic property of BFO microcrystals were investigated. The analysis reveals that the hydrolysis of urea in the hydrothermal process plays a key role in the synthesis of pure phase BM microcrystals. FE-SEM and TEM results show that these BFO microcrystals present a nearly spherical microstructure, and specially exhibit superstructures consisting of large amounts of small particles with the size of 100-150 nm by further observation. Moreover, these BFO microcrystals exhibit efficient photocatalytic activity under visible-light irradiation, suggesting their promising applications as photocatalysts and related fields. (C) 2012 Elsevier Ltd. All rights reserved.