Gold was recovered from outsourcing gold cyanide tailings from a gold plant of Shaanxi. Gold grade of tailings is 2.21 g/t, gold carrier mineral pyrite is partial oxidized, gold recovery by flotation of is difficult. To find the appropriate activator, activation flotation experiment was carried out using ammonium sulfate and copper sulfate. Results show that the tail slag ground to -0.044 mm 92% and via three roughing-one scavenging, rough concentrates mixed and selected gold, when using ammonium sulfate as the activator, concentrate with gold grade of 33.80 g/t and recovery of 39.78% was obtained. Compared with copper sulfate, gold grade and recovery increased 6.9 g/t and 1.07 percentage points, and with lower sulfur content in tailings. So ammonium sulfate can be used instead of copper sulfate as the gold cyanide tailings activating flotation, and the economic benefit is remarkable, results can be used for reference in the similar tailings flotation for gold recovery.