The invention relates to cesium tungsten bronze powder and a preparation method thereof. The method comprises the following steps that: 1, precursor solution with tungstic acid, cesium carbonate and reducing substances is prepared according to a Cs / W mole ratio of 0.01 to 0.35 / 1, and the solvents are water or a mixture formed by ethanol and the water according to a volume ratio of 1 / 4 to 4 / 1; and 2, the precursor solution takes reaction for 1 to 3d under the condition of 180 to 200 DEG C in an autoclave, and the cesium tungsten bronze powder is obtained after the obtained precipitates are treated. The powder has the crystalline phase composition of Cs0.2WO3 or Cs0.32WO3, the size of the powder particle is 100 to 1300nm, and the specific surface area is 7 to 50m<2> / g. The synthetic process has the advantages that raw materials are cheap and mild, the operation is easy, the production cost can be reduced, in addition, the low-temperature (lower than or equal to 20 DEG C) synthesis is adopted, and the process is suitable for production and practical application. In addition, the product purposes are wide.