Abstract: A brief account is made in the paper of the background of the development of the secondary flotation process,as well as the necessity to apply the renovated secondary flotation process at Guobei Coal Preparation Plant as viewed from the angles of experimental data and flotation indices.As evidenced by the comparison of the techno-economic indices of the flotation circuit before and after the renovation,the application of the renovated secondary flotation process has led to reduced concentrate ash,increased concentrate yield,more consistent flotation products and much improved economic result.