The invention relates to the field of dangerous solid waste environmental protection treatment and resource generation, and specifically discloses a cooperative treatment method for chromium-containing heavy metal sludge and iron-containing dust sludge. The method comprises the following steps of: mixing the chromium-containing heavy metal sludge with the iron-containing dust sludge, thereby preparing a mixture with total iron mass percentage content higher than or equal to 25%; then, adding a fixing agent and a flux to uniformly mix and pelletizing, thereby obtaining green pellets; drying thegreen pellets, mixing the green pellets with a reducing agent, directly reducing the green pellets mixed with the reducing agent to obtain a roasted product; and adopting wet-type weak magnetic separation after roasted product ore grinding, thereby obtaining a ferrochrome alloy product and tailings. Through cooperative treatment for the chromium-containing heavy metal sludge and the iron-containing dust sludge, the ferrochrome alloy product can be obtained, and the obtained tailings can be treated as common solid waste; and meanwhile, harmless and resourceful treatment of the chromium-containing heavy metal sludge and the iron-containing dust sludge is realized.