In order to study the feasibility and effectiveness of full jet longitudinal smoke exhaust in a 6 km highway tunnel, the full jet longitudinal smoke exhaust field fire test is conducted in Yanglushan Tunnel. The fire test of three grades of 5 MW, 10 MW and 20 MW are carried out in the left tunnel of Yanglushan Tunnel, which is a downhill tunnel that is not conducive to smoke exhaustion. During the fire test, the wind velocity along the tunnel and smoke exhaust time in the tunnel under different fire conditions are studied. Through the field test of oil pool fire under different fire conditions, the research results are as follows: (1) The natural wind velocity in the left tunnel of the Yanglushan Tunnel is 1.0-1.6 m/s during the field fire test, and the wind direction is opposite to the direction of smoke exhaust, which is resistance for smoke exhaust. (2) The wind velocity is greater than 3.0 m/s along the downhill tunnel when more than 6 groups of jet fans are started up. (3) According to the oil pool fire smoke test results of fire heat release rate of 5 MW, 10 MW and 20 MW, all smoke can be exhausted completely outside the tunnel through full jet longitudinal exhaust method, and the time from fire ignition to smoke exhaustion completed is about 30 min.