This paper describes a method for treating Pb(Ⅱ) wastewater by natural iron_bearing sulfides. The process of the experiment is as follows: the natural mineral sample is obtained through selection, followed by determination, smashing, washing, drying, screening, magnetic separation and identification according to its X_ray diffraction property; then the Pb(Ⅱ) wastewater is prepared by solving solid Pb(NO3)2in the distilled water, and the pH of the solution is changed by 1% HNO3and 5% NaOH solution; at last the sample is put into the Pb(Ⅱ) solution to make them react with each other. The experimental results show that the increase of the quantity of the sample, the decrease of the grain size of the sample, the raising of the initial pH and Pb(Ⅱ) concentrations and the reduction of the volume of the Pb(Ⅱ) solution are beneficial to the decrease of Pb(Ⅱ) ion amount that dissolves in the solution. On the basis of the initial Pb(Ⅱ) ion concentration value (c), an equation for the quantity of the sample (m) has been obtained, viz., pH=11.00,m=0.2006c+0.4244,m:g,c:μg/ml.Some reaction mechanisms on treating Pb(Ⅱ) by the natural iron_bearing sulfide have also been dealt with in detail in this paper.