Abstract: The performance and mechanism of the concrete of artificial reefs preparedby Qidashan iron tailings as main raw materials were studied. The research showed that when the additional ratio of iron tailings was 70%，the compressive and flexible strength of concrete for 28 days of standard curing were up to 47.3 MPa and 8.6 MPa，respectively. The iron tailings powder with the specific surface of 720 m²/kg，has a certain of pozzolanic activity，which plays excellent filling effects in the concrete of artificial reefs. During the early period of seawater immersion of artificial reefs blocks，a small amount of OH- was dissolved out of the surface，resulting in the pH value of leaching solution rising from fresh seawater 8.0 to 8.5，but back to normal value after 69 d. Test results of heavy metal ion released indicated that the leaching solution could meet up the national water quality standard for fisheries. Hence，concrete of artificial reefs with high content of iron tailings not only have good mechanical performance，but also have low-alkali and non-pollution properties，which meet the demands of artificial reefs. It shows good marine adaptability，and makes comprehensive utilization of iron tailings and marine fishery proliferation possible.

Key words: Iron tailings, Concrete of artificial reefs, Reactive powder, Marine adaptability