The smoke characteristics of tunnel fire are preliminarily concerned with the heat release, the tunnel geometry, smoke outlet geometry, etc. However, the study on smoke characteristics of tunnel fire with different cross passage interval is relatively less at present. Base on the physical model of a large scale cross-section road tunnel, this paper carried out simulation and analysis on the smoke flow of several fire scenarios under different cross passage interval through FDS 5.4.3. The results demonstrated that in a certain extent while the cross passage interval was less than 400m, the longer the cross passage interval was, the longer the time when the smoke began to counter flow in the tunnel and the longer the length of counter-flow smoke. If the cross passage interval was beyond this scope, the time that the smoke began to counter flow and the length of counter-flow smoke tended respectively to be the same.