The present invention relates to a method and an apparatus for producing China V vehicle diesel oil through liquid-phase hydrogenation. The apparatus comprises a hydrogenation reactor, a hot high pressure steam stripping separator, a gas pipeline, a circulation pump, an ammonia method desulfurization device, a circulation hydrogen desulfurization tank, a circulation hydrogen compressor, a liquid separation tank, a water cooler, an air cooler, a heat exchanger, a cold low-pressure separator and a hot low-pressure separator, wherein a diesel oil raw material is subjected to a hydrogenation reaction in the hydrogenation reactor, the reaction product is separated in the hot high pressure steam stripping separator to obtain the liquid product, the liquid product enters the hot low-pressure separation tank, the separated gas product enters the liquid separation tank so as to be subjected to gas-liquid separation, the liquid phase separated through the liquid separation tank is subjected to heat exchange, the obtained liquid phase enters the cold low-pressure separator, the separated hydrogen gas enters the circulation hydrogen desulfurization tank so as to be subjected to desulfurization, the desulfurized circulation hydrogen is subjected to pressurization and heat exchange, and the obtained circulation hydrogen respectively enters the hot high pressure steam stripping separator, the hydrogenation reactor and the fresh raw material mixing tank. According to the present invention, the circulation hydrogen is subjected to desulfurization through the desulfurization system, such that the hydrogen sulfide content in the circulation hydrogen is reduced, the sulfur content in the hydrogenation diesel oil is reduced to less than or equal to 10 ppm, and the diesel oil product quality is improved.