The invention discloses a homogenizing treatment method for corrosion resistant plastic mold rolled flat steel. The homogenizing treatment method includes the following steps that ingot reds with themeasured temperature no less than 700 DEG C are sent to a primary rolling workshop to be subjected to furnace charging and fast heating to the heat preservation temperature of 1200-1300 DEG C, and theingots are heat preserved for 4.5-5.5h; the furnace temperature is reduced by 70-90 DEG C, the ingots are heat preserved for 0.8-1.2h, and then out of a furnace to be rolled into steel billets with 250-300mm*660-680mm; the steel billets are all back to the furnace and subjected to heating to the heat preservation temperature of 1200-1300 DEG C, and then subjected to heat preservation for 18-22h to be subjected to internal homogenizing treatment; the furnace temperature is reduced by 80-120 DEG C, the steel billets are heat preserved for 1h, and then out of the furnace to be rolled to the final size; and the surface of the steel billets after homogenizing treatment is polished and then transferred to the next process to be rolled into the finished flat steel. According to the homogenizingtreatment method for the corrosion resistant plastic mold rolled flat steel, the process is simple, both economy and practicability are very high, the steel for a plastic mold manufactured by using the homogenizing treatment method has a high pass rate, can reach the level of high density and high homogeneity with uniform composition, structure and hardness, and has made sufficient homogenizationpreparation for subsequent cold processing, heat treatment, and the like by users.