Abstract: Based on the blended coal coking test in 40 kg coking oven with gas blended with 1 /3 coking coal,fat coal and coking coal,the coking coal thermal property, pore structure,SEM and other characteristic means were applied to observe the macro and micro structure variation of the coke and to study the interaction mechanism bet ween the gas coal and other coking coal. The study results showed that in the blended coal coking,the fat coal would have high containment capacity to the gas coal and g as blending rate should be controlled based on fat coal as the base. With the gas coal blending rate increased,each pore parameters of coke would be varied obviously and the thermal property of coke would steadily be deterioration and would have a serious deterioration point. The coking with the gas coal affected to the coke thermal propert y mainly to realize by the pore structure changed.