The invention discloses a regeneration liquid and a regeneration method for an iron poisoning deactivation hydrodesulfurization catalyst. The regeneration liquid comprises, by weight, 3-20 wt% of oleic acid, 50-70 wt% of water, and 10-47 wt% of an extraction liquid, wherein the extraction liquid is diethyl ether and/or benzene. The regeneration method comprises: (1) sequentially carrying out oil firing, sulfur firing and carbon firing on a hydrodesulfurization catalyst being subjected to iron poisoning deactivation; and (2) adding the catalyst treated in the step (1) to the regeneration liquid, soaking, carrying out standing layering, filtering the catalyst in the water phase, washing, drying, and calcining to obtain the regenerated catalyst. With the method of the present invention, the iron poisoning catalyst is effectively regenerated, such that the pore volume, the specific surface area, the side compressive strength and the hydrodesulfurization activity of the catalyst are recovered.