The invention discloses a microwave hydrothermal preparation method of NiTiO3 nano powder, comprising the following steps: adding nickel nitrate hexahydrate in ethanol to obtain a solution A; adding tetrabutyl titanate, citric acid, water and acetylacetone in the solution A to obtain a solution B; pouring the solution B in a hydro-thermal reaction kettle, selecting a temperature controlling mode or a pressure controlling mode to react, and cooling naturally to the room temperature after reaction; and opening the hydro-thermal reaction kettle, centrifuging, separating and collecting products, washing with deionized water, absolute ethyl alcohol or isopropanol respectively, and drying in an electrothermal blowing dry box to obtain the final product NiTiO3 nano powder. The reaction can be finished in liquid phase in one time, post-treatment is avoided, the process equipment is simple, and the obtained nano powder has the advantages of small grain diameter, good dispersibility, short reaction period, favorable repeatability and wide development prospect. The NiTiO3 nano powder prepared by the method in the invention has the characteristics of smaller crystal grain size, good dispersibility, evenly-distributed grains, less conglobation and no impurity.