Abstract: The high sulfur content will reduce the strength of backfill.Adopting pyrite concentrate and sulfur tailings to control the sulfur content of tailings，the sulfur tailings effect on setting time and strength of filling body is studied，and according to the research results，two control measures of adding sodium silicate and citric acid are put forward.The results show that with sulfur content of tailings increasing，slurry setting time is longer，filling body strength reducing.The strength of backfill with less than 18% sulfur content is more than 1.2 MPa and the tailings can be used as filling aggregates.The sodium silicate is less than 4%，the accelerating effect is obvious.However，due to the formation of secondary expansion phase，the filling body 28d strength reduces gradually.When the citric acid is 0.3%，the increase of the setting time of the slurry is not obvious，and the body 28d strength reaches 1.0 MPa，and not decrease with the extension of curing time and meets filling requirements.Because the body early strength is restrained，its structure is loose，the secondary expansion phase is formed continuously to fill the pore between hydration product，making the body interior further dense.

Key words: High sulfur tailings, Sulfur content, Filling properties, Sodium silicate, Citric acid