In order to reveal the influence of guide vane structural parameters on sealing efficiency and disk cavity flow field，with adding user defined scalar(UDS) in the mainstream to simulate gas ingestion,the effects of guide vane angle,axial position and solidity on sealing characteristics of rim seal were studied by using periodic 3-D numerical method.The results show that after the fluid flows through the guide vane,it will separate and slow down at the trailing edge,thus forming a high pressure region downstream of the trailing edge,and its distribution form is similar to sinusoidal distribution along the tangential direction.There are two forms of externally induced gas ingestion,namely,mainstream flow ingestion induced by the separation and decelerate of mainstream flow at the trailing edge of guide vane and the increase of pressure,the mainstream flow ingestion induced by the speed stagnation when the mainstream flow impact the outer edge of the disk and the increase of pressure.The axial direction of ingestion position is near the rotational disk side,and the tangential direction is the position with the highest pressure at the trailing edge of the guide vane.At high rotational Reynolds number,the mainstream flow ingestion is induced by rotation,and the change of guide vane structural parameters has little effect on sealing efficiency.At low rotational Reynolds number,the tangential pressure inhomogeneity is further enhanced with the increase of guide vane angle,and the sealing efficiency is decreased by 5%.The tangential pressure inhomogeneity is weakened with the increase of guide vane axial position,and the sealing efficiency is increased 28%.The tangential pressure changes little with the increase of guide vane solidity,but the tangential velocity of the mainstream increases significantly thus increasing sealing efficiency by 30%.