Thermo-gravimetric analysis is performed to study the combustion performance of upgraded low rank coal，bituminous coal injected into blast furnace and their mixture.It’s studied the relationship between adding quantity of upgraded low rank coal and change rules of blended coal combustion index and their influence on each other.Blended combustion kinetics is analyzed by using the distributed activation energy model (DAEM).The results indicate that the combustion rate of upgraded low rank coal is faster than that of bituminous coal.With the increase of adding quantity of upgraded low rank coal in the blended coal，the ignition temperature gradually decreases，the combustible index and comprehensive combustion index increase，and burning effect gets better.The value of interaction factors K of all blended coals are greater than 1，which suggests that the mutual promotion between upgraded low rank coal and bituminous coal in the combustion process exists.The apparent activation energy of blended coals decrease with the increase of adding quantity of upgraded low rank coal，which indicates the combustion activity of blend coal gradually stronger.