Three full scale tests were conducted in a road tunnel to study the smoke spread with different fire sizes and wind speed conditions. The smoke temperature under the ceiling, the smoke layer height distribution and the travel of the smoke front in a 1000 m long domain along the road tunnel were measured. Results showed that wind speed had much influence on the spread of smoke in the tunnel. When wind speed was such low as less than 1 m/s, a smoke layer could form and stabilize all along the tunnel. But when the wind speed was such high as more than 2 m/s, smoke layer could only be maintained in a distance of about 400 m in the downstream. The slowdown of the traveling of the smoke front in the downstream along the tunnel was more obvious when the wind speed was smaller. All these full scale data presented here can be used for further study on the verification or improvement of existing fire models for enhancing their applicability to such long tunnels.