The invention relates to a gel casting preparation method of a nickel oxide-based ceramic target material. The gel casting preparation method comprises the following steps of A, preparing raw materials, B, preparing a premixed solution, C, preparing high-fluidity slurry, D, preparing a biscuit, E, degumming the biscuit: carrying out gradient heating on the biscuit, and carrying out furnace coolingto obtain a degummed blank, F, sintering: specifically, enabling the blank to be subjected to vacuum gradient sintering with the first gradient temperature of 650-800 DEG C, the temperature rising speed not higher than 1.5 DEG C / min, and the heat preservation time not shorter than 2 hours, heating to a second gradient temperature of 900-1200 DEG C at a heating speed of not higher than 1 DEG C / min, keeping the temperature for not less than 5 hours, cooling and molding, and G, machining, specifically, conducting or not conducting machining according to needs. The preparation method can be usedfor preparing the nickel oxide-based ceramic target material with good conductivity, higher purity and fine grain size, and is simple and convenient to operate and low in cost.