The carbon composite agglomerates have been numerically examined. The previously presented multi-fluid blast furnace model is modified to simulate blast furnace operation with carbon composite agglomerates charging. The model considers the behavior of carbon composite agglomerates, namely, conservation equations of chemical species contained in this material including chemical reactions and phase transformations are newly added. A series of simulating calculations are performed to examine the effect of charging carbon composite agglomerates. The result reveals that with increase in carbon composite agglomerates charging ratio in-furnace temperature level tends to decrease, the location of cohesive zone shifts downward, and the reductions of carbon composite agglomerates and sinter are delayed. On the other hand, the productivity tends to increase while coke rate and total reducing agent rate show decrease. The energy consumption for unit production of hot metal is lowered. The performance of blast furnace is improved in the tested range mainly due to the decrease in heat requirements for solution loss, sinter reduction and silicon transfer reactions, heat outflow by top gas and wall heat loss.