Abstract In this study, a simple route for the synthesis of hierarchical W 18 O 49 assembled by nanowires is reported. The morphologies and formation of W 18 O 49 single-crystal could be controlled by changing the concentration of WCl 6 -ethanol solution. This synthesis strategy has the advantages that the hierarchical W 18 O 49 microspheres could be economic synthesized at 180 °C without adding additives. Furthermore, efficient optical absorption properties in ultraviolet, visible and near-infrared region were obtained for the hierarchical W 18 O 49 microspheres comparing with nanowires. These results will further promote the research of tungsten-based oxide nanomaterials. Graphical abstract