The bonding of sintering grate bars is the important cause of their failure and life reduction, and it has a negative influence on the sintering process, sinter output and the quality. In order to solve this problem, through sampling of large number of bonding materials of Jingtang sintering grate bars for a long period of time, systematic investigations for their composition and the microstructure are carried out, and it is confirmed that KCl is a necessary but not sufficient condition for the bonding of grate bars. KCl promotes the corrosion of Fe and Cr oxides in grate surface, which is the direct cause of the decrease of grate bar life. The effective measures for control of Jingtang sintering grate bars are proposed as follows: The K₂O and Cl content of blended ores are controlled as < 0.06% and < 0.05%, and K₂O and Cl content of sintering mixture are controlled as < 0.09% and < 0.05%. After the measures were implemented, the bonding problem of the grate bars in Jingtang sintering was finally and completely solved with service life increasing from 12 to 22 months.