Abstract: Ceramsite filter was prepared using iron tailings as main raw material，adding small amount of fly ash，coal gangue，limestone and admixture，and COD removal efficiency by ceramsite was investigated.Results indicated that: with the iron ore tailings，fly ash，coal gangue，limestone，biological mass percentage of 86%，6%，4%，3%，1%，respectively，ceramic diameter of 3~5 mm，roasting temperature of 1 100 ℃，the COD removal rate in domestic sewage by ceramsite can reach 80%.XRD and SEM analysis results indicated that: sodium feldspar generated during roasting increases the strength of ceramsite，at the same time，ceramsite has good adsorption performance for its rough surface，large amount of internal porous，and large specific surface area，which is helpful for pollutant removal in domestic sewage.

Key words: Iron tailings, Ceramsite, Domestic sewage, COD