A new nickel zinc chromate with the composition of (NH4OH)3/2NiZn2Cr2O9⋅2H2O was synthesized by hydrothermal method. The compound was characterized by XRD, TGA, and XRF. X-ray powder diffraction data show that the crystal system of the title compound is hexagonal with space group R-3m, z=3, and unit-cell parameters: a=5.9794 and c=21.4875 Å.