To explore the mechanism of aeroelastic instability of labyrinth sealing,the structure dynamics and aeroelastic stability criteria of labyrinth seal were analyzed theoretically.A numerical model for solving the aeroelastic stability of labyrinth seals was established,and the accuracy of the numerical method was verified.The influences of labyrinth seal ring cavity width,wall thickness and rotating speed on the natural frequency and aeroelastic stability of labyrinth seal were studied.The influence mechanism of aeroelastic instability of labyrinth seal was revealed.The results show that the influences of cavity width and wall thickness on natural frequency increase with the increase of nodal diameter number,and have little effect on the first three natural frequencies.The increase of the labyrinth seal ring cavity width lead to the decrease of the natural frequency and the aeroelastic stability.The increase of labyrinth seal wall thickness lead to the increase of natural frequency and effectively improve the aeroelastic instability.Increasing rotational speed cause significant increase in the labyrinth seal natural frequency and has little influence on the aeroelastic stability.