Abstract: Cementitious materials is prepared with molybdenum tailings，slag，clinker and gypsum，which were milled separately.The effects of cementitious materials content and sand ratio on mechanical performance of the concrete were studied.The experiments indicated that，with cementitious materials content increasing，slump and compressive strength of the concrete increased.With sand ratio increasing，slump and compressive strength of the concrete increased first and then decreased.When the mass ratio of cementitious materials and aggregate is 1∶3 and sand ratio is 0.35，the compressive strength of molybdenum-tailing-based concrete is high up to 68.7 MPa at curing for 28 d.The hydration products of cementitious materials prepared with molybdenum tailings，C-S-H gel，ettringite and iron hydroxide gel were intertwined.Some fine grains which was not involved in the reaction were filled into the pore，so the compressive strength of cementitious materials was promoted.

Key words: Molybdenum tailings, Concrete, Compressive strength, Slump