The invention relates to a mild hydrogenation extraction method for direct coal liquefaction oil, which comprises: blending the direct coal liquefaction oil with hydrogen to put into a steady hydrogenation reactor, carrying out desulfurization, denitrification, olefin saturation and aromatics saturation reaction under the action of a hydrotreating catalyst, separating and distilling the reaction product to obtain naphtha cut and diesel distillate, blending the obtained diesel distillate with the hydrogen, putting the mixture into a hydrogenation modification reactor to contact and react with a hydrogenation modification catalyst, separating and distilling the reaction product to obtain the diesel product. The method provided by the invention effectively combines a steady hydrogenation unit with a hydrogenation modification unit, and can product the diesel product with more than 45 of cetane number. The method has the advantages of mild operation condition, simple process, low investment, and low operation expense.