The invention relates to a multistage bioleaching reactor process and equipment for sludge treatment. The equipment comprises bioleaching reactors of multiple stages, a sludge thickening pool, aeration devices, an internal sludge reflux pump, an external sludge reflux pump, a dewatering pump, a box type press filter and the like. Composite microbial flora mainly comprising acidophilic thiobacillus, acid-resisting heterotrophic bacteria and the like is utilized, sludge is subjected to acidification in the bioleaching reactors of multiple stages under the condition that the composite microbial flora is matched with nutritional substances in an aerobic environment with appropriate temperature, finally, the pH value is decreased to be smaller than 3, heavy metals in the sludge are transferred into an aqueous phase, and mud cakes with moisture content lower than 60% can be obtained through press filtering and dewatering. The aeration devices adopt flow jetting aeration or centrifugal flow diffusing aeration, so that the power consumption is decreased by over 30% compared with that of air blasting aeration. After the sludge is subjected to bioleaching reaction, no more odors are generated, pathogenic microorganisms of over 99% are killed, the dewatering is easy, the moisture content of the mud cakes is lower than 60% in the case of not adding any medicaments, and the amount of the sludge is reduced greatly.