Abstract: The aim of wind tunnel experiment of ram air turbine was mainly to simulate the real flight refuel conditions on the basis of employing similarity criteria.In the meantime,the output power of the turbine was measured,and its aerodynamic characteristics were further analyzed.An exciter motor generator and a refueling pump were used as the dynamometer machine.The maximal output power could be obtained by means of adjusting the pitch of ram turbine blades.It was found that the output power of ram air turbine can satisfy the flight refuel needs on conditions that the air speed of wind tunnel is 16% lower than the minimal flight speed of aircraft tanker.The Baldwin Lomax turbulence model with highly numerical stability was used to simulate the 3 D internal and external mixed flow fields of ram air turbine.The main dynamic parameters of turbine flow field were investigated and the cause of load distributing on the blades surface was also discussed.It was revealed that the ram air turbine performance could be improved by optimizing the blades near the hub region.