Core-shell structured ZnO/In2O3 composites were successfully synthesized via situ growth method. Phase structure, morphology, microstructure and property of the products were investigated by X-ray diffraction (XRD), TG-DTA, field emission scanning electron microscopy (FESEM), energy-dispersive spectrometry (EDS), transmission electron microscope (TEM) and photoluminescence (PL). Results show that the core-shell structures consist of spindle-like ZnO with about 800 nm in length and 200 nm in diameter, and In2O3 particles with a diameter of 50 nm coated on the surface of ZnO uniformly. HMTA plays an important role in the formation of core-shell structures and the addition of In2O3 has a great effect on PL spectrum. Possible mechanism for the formation of core-shell structures is also proposed in this paper. Crown Copyright (C) 2011 Published by Elsevier B. V. All rights reserved.