Aiming at the defects that skinned high-temperature cooked raw materials are energy-wasting, high-temperature cooking causes volatilization of oil in the raw materials, damages the nutritional ingredients in grease and reduces the flavor of the plant oil, and the volatilizing oil ingredients are mixed in atmosphere and cause environment pollution in the existing plant oil hot-pressing technology, the invention provides a preparation method of warm-pressed plant oil. The preparation method comprises the following steps: raw material selection, raw material cleaning, stone removal, skinning, embryo pressing, gradient temperature cooking, warm pressing, filtration, refined filtration, finished product formation. The plant oil produced by the method has a high oil yield, pure color, a nose greeting aroma and guaranteed quality; in addition, the method is energy-saving and does not pollute environment during production.