Effects of the concentration of ZrOCl2, calcination temperature, heating rate, and the size of secondary particles after hydrolysis on the preparation of high‐purity ZrSiO4fine powders from ZrOCl2.8H2O (0.2Mto 1.7M) and equimolar colloidal SiO2using sol–gel processing have been studied. Mechanical properties of the sintered ZrSiO4from the high‐purity ZrSiO4powders have been also investigated. Single‐phase ZrSiO4fine powders were synthesized at 1300°C by forming ZrSiO4precursors having a Zr–O–Si bond, which was found in all the hydrolysis solutions, and by controlling a secondary particle size after hydrolysis. The conversion rate of ZrSiO4precursor gels to ZrSiO4powders from concentrations other than 0.4MZrOCl2.8H2O increased when the heating rate was high, whereupon the crystallization of unreacted ZrO2and SiO2was depressed and the propagation and increase of ZrSiO4nuclei in the gels were accelerated. The density of the ZrSiO4sintered bodies, manufactured by firing the ZrSiO4compacts at 1600° to 1700°C, was more than 95% of the theoretical density, and the grain size ranged around 2 to 4 μm. The mechanical strength was 320 MPa (room temperature to 1400°C), and the thermal shock resistance was superior to that of mullite and alumina, with fairly high stability at hig