It is well known that Hg(Ⅱ) is seriously harmful to public health. For example, it impairs such parts of human bodies as brain neuron, kidney and heart tissue. So it is necessary to remove the Hg(Ⅱ) from wastewater before it is discharged. A method for the treatment of the Hg(Ⅱ) wastewater by using natural iron_bearing sulfide is reported in this paper, and the effects of pH, concentration of Hg(Ⅱ) and grain size of the sample upon removal of Hg(Ⅱ) in wastewater are studied in detail. In addition, the characteristics of the repeated utilization of the sample as well as the relationship between Hg(Ⅱ) concentration and wastewater volume and quantity of the sample are discussed. It is emphatically pointed out that the rate of Hg(Ⅱ) precipitation can be raised by increasing pH value from the beginning to the end of the treatment. The experimental results show that the method is very effective in the treatment of Hg(Ⅱ) wastewater.