Abstract: The standard k-ε turbulence model and RNG k-ε turbulence model were employed to compute the flow characteristics of the labyrinth sealing in the given reference.Compared to their test data,the maximum errors were 2.5% and 15.9% respectively.The computations of annular straight-through sealing with four-tooth and seven-tooth at rotational and static states were carried out with the non-structure grid and SIMPLE method.The sealing effects for different number of tooth and rotational speeds were experimentally investigated.The relations between pressure ratio and leaking coefficient were also explored.The results show that the rotational speed plays a small role on sealing effectiveness,and makes a change of the leaking coefficient within 3.6%.Under low pressure ratio condition,the leaking coefficient goes up a little with the increase of pressure ratio with the same change of Taylor number.