The invention relates to a method for sulfur activation floatation in copper tailings in copper sulfide sulfur ores and belongs to the technical field of nonferrous metal ore-dressing. The method comprises the steps that the copper sulfide sulfur ores are taken to be ground, before ore grinding, calcium oxides are added to enable the pH value of flotation pulp to reach 11.5, the copper sulfide sulfur ores are ground to the level that the mass of screen underflow with the particle size being smaller than 0.074 mm accounts for 70% of that of the taken copper sulfide sulfur ores, and then water is added till the mass percent concentration of the pulp reaches 30%; 140 g/t of sodium sulfide, 30 g/t of butyl xanthate and 25 g/t 2#oil are added into the obtained pulp for copper sulfide flotation,and thus copper rough concentrates and the copper tailings are obtained; acid wastewater is added into the copper tailings till the pH value of the pulp is 9.0-9.5; and 60 g/t of butyl xanthate and 20 g/t 2#oil are added into the obtained pulp for sulfur flotation, and thus sulfur concentrates are obtained. According to the method for sulfur activation floatation in the copper tailings of the copper sulfide sulfur ores, the acid wastewater in a mine is utilized reasonably, the production cost of the mine is lowered, and pollution of the mine to the natural environment is reduced.