The invention discloses a distribution system and a distribution method for an ultrahigh double-width cast-in-place concrete beam. The distribution system comprises a concrete high-pressure trailer pump, concrete conveying pump pipes, continuous beam construction bracket vertical posts, a second-width pier top distributor embedded part, a first-width continuous beam top distributor embedded part, a distributor, a first-width continuous beam, first-width pier bodies, a first-width pier body, second-width continuous beams and construction segmentation lines. The distribution system and the distribution method have the advantages that concrete is poured into beam bodies under coverage through the distributor after concrete is pumped to pier tops or beam surfaces through the high-pressure trailer pump, and continuous and rapid pouring of beam body concrete is realized along with the rotation of distribution rods, so that time for detaching, connecting and moving the pump pipes in a concrete pouring process is shortened, high workability and continuity of concrete are ensured, the concrete performance is ensured, and the construction quality risk is lowered. Meanwhile, due to the use of the distributor, manual arrangement on a high-altitude operation field is reduced, the working efficiency is increased, and the manual safety is enhanced. The distribution system and the distribution method have the advantages of small investment, low cost, convenience in construction and high popularization value.