Abstract: Nickel molybdate is an important catalyst，whose catalytic activity is subject to its phase structure and morphology. Micro/nano nickel molybdate with different morphologies had been successfully prepared via hydrothermal technique using ethylenediaminetetraacetic acid disodium salt dihydrate as shape-control agent under different pH.X-ray powder diffractometry， transmission electron microscope，and scanning electron microscope were employed for the characterization and analysis of the phase，morphology，and size of the resulting products.Results indicated that the complexation additive played a key role for the formation of micro/nano nickel molybdate rods.Corresponding micro mechanism of complexation additive controlling morphology was also preliminarily discussed. 

Key words: nickel molybdate, EDTA, special morphology, hydrothermal synthesis