The invention relates to an iron-carbon micro-electrolysis filler; the iron-carbon micro-electrolysis filler takes activated sludge as an adhesive, and is prepared by the following steps: 1) manuallycracking whole section of jujube charcoal into small particles, putting the small particles into a powder mill, grinding into powder, and sieving the powder with a 30-mesh sieve to obtain carbon powder; 2) taking waste iron scraps generated in an iron product machining process as iron powder; 3) taking residual sludge as an adhesive; 4) putting the charcoal powder and the iron powder into a container according to a ratio, and fully and uniformly mixing; 5), adding activated sludge into the mixed charcoal powder and iron powder according to a certain ratio and uniformly stirring; 6), putting the mixed material into a mold, beating for several times, and demolding; and 7), drying after standing in a natural state for 24 h, and thus obtaining the iron-carbon filler. The iron-carbon filler hasthe advantages of simple process, convenient preparation, low cost, energy saving and environmental protection.