High purity ZrSiO4 powders were prepared using zirconium oxychloride and tetraethoxysilane as raw materials by the microwave hydrothermal (M-H) method, in which NaF was added as mineralizer to promote the crystallization of zircon. The results show that the microwave-hydrothermal method greatly reduces the starting crystallization temperature of ZrSiO4 powders to 160~200 °C in 30 minutes, the characteristics of the microwave hydrothermally synthesized powders are superior to that synthesized by conventional hydrothermal in stability, purity and morphologies. And the XRD analysis shows that all peaks of the former powders are abnormal broadness except the (200) and (220) peaks, and the crystallization of powders can be improved by adding seed crystals of ZrSiO4. The ZrSiO4 particles are disk-like platelets which are monocrystal and have a trend of Single crystal to polycrystalline transition. The synthesis mechanism of ZrSiO4 by microwave hydrothermal (M-H) process is discussed.