Abstract: Experiments about the coke reactivity and slag viscosity were performed with the medium-low temperature reduction and coke reactivity device of iron ore and the high-temperature melt property tester, and the effects of unburned pulverized coal on the properties of coke and slag were studied. The results show that the unburned pulverized coal can play a role in protecting coke, when the mass fraction of unburned pulverized coal increases from 0 to 9%, the coke after reacting strength (CRS) increases from 72.0% to 76.4%, and the coke reactivity (CRI) decreases from 23.5% to 16.1%; the unburned pulverized coal as solid particles in the melt makes the slag increase, when the mass fraction increases from 0 to 8%, and the slag viscosity increases from 0.266 Pa·s to 0.591 Pa·s, while the mass fraction increases to 10%, the slag viscosity increases sharply to 0.824 Pa·s.