Abstract: Aeroelastic stability of the labyrinth gas seals is important.Labyrinth seal vibrates as nodal diameter along the circumference,the reducing of aerodynamics damping in some mode makes the stability of the system reduced,even makes the system unstable.We used the double control volume model to calculate the aerodynamics damper and aerodynamics stiffness of the labyrinth seals under nodal diameter vibration,and analyzed the stability of the labyrinth seals according to the complex values which was calculated by the finite element software.