Abstract: Thiobacillus collected from waste water in iron ore well was used to transform sulphide in the iron ore. The addition of phosphorus dissolving agent enhanced the dissolution of phosphorous to decrease the content of phosphorus in iron ore below 0. 2%. This biological technique may also be used to prepare iron-phosphorus composite fertilizer from waste water of the tailings so as to reduce environmental pollution, and to develope the comprehensive utilization of national resources.