The present invention discloses a diesel hydrogenation modification method, the method comprises the following steps: raw material diesel and hydrogen are sent into a reactor for contact with a hydrogenation catalyst to obtain a liquid phase material flow; the hydrogen is sent into a liquid phase material stream by holes with an average pore size of nano-size to obtain a hydrogen-containing liquid stream; the hydrogen-containing liquid material stream is sent into a tubular reactor in the upwardly flowing manner for contact with the hydrogenation catalyst under the liquid phase hydrogenation processing conditions to obtain a diesel product. The present invention also provides a hydrogenation processing device, the hydrogen is injected, by a gas and liquid mixer, into a liquid phase material stream obtained by a first hydrogenation reactor, the gas and liquid mixer is between the first hydrogenation reactor and a second hydrogenation reactor, and the second hydrogenation reactor is the tubular reactor. According to the method, even the use amount of the hydrogen is reduced, and operation is performed at a higher space velocity, clean diesel with the sulfur content not greater than 50mug / g, or even not greater than 10mug / g can be obtained.