In this paper, Cesium Tungsten Bronze (Cs_xWO₃) powders was synthesized by hydrothermal method. Effects of cesium content of reactant and concentration of citric acid on crystalline phases, micromorphology and size of Cs_xWO₃ powders were studied. The Cs_xWO₃ was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and DLS. The results show that we can get higher crystallinity, smaller diameters and well dispersed Cs_xWO₃ powders at 200℃ for 3 day through moderately increasing the cesium content of reactant and the concentration of citric acid.