Abstract: According to the situation of coal using in Beiying coking plant，the weighted active inert ratio is calculated through the vitrinite active weight function equation，and the optimized coal blending and coking experiment is carried out. Then the relation curve between coke CSR and coking coal weighted active inert ratio is obtained. The best weighted active inert ratio of blended coal is in the range of 2.8～3.2. Based on this principle，on the premise of coal blending and coking experiment and ensuring coke quality，the ratio of coking coal and fat coal can be reduced, and that of 1/3 coking coal and lean coal is increased，so as to lower the coal blending cost. The result shows that the weighted active inert ratio of coal is closely related to the CSR of coke，and the correlation coefficient is R=0.919. From the experience of coke oven production，coke quality can be improved when strong caking coal is reduced by 8%

Key words: Coking coal, Weighted active inert ratio, Coke quality, Coal blending cost