Labyrinth seal can cause steamexciting,the structural and operating parameters of labyrinth seal have effect on stability of rotorsystem.For investigating the coupling influences of the structure and operating parameters of labyrinth seals on dynamic coefficients,a model of calculating dynamic coefficients of labyrinth seals is presented using a two control volume model.The coupling influences of parameters on crosscoupled stiffness and direct damping of labyrinth seal are discussed.In the conclusion,a reference of preventing steamexciting vibration and optimum determination of design parameters of labyrinth seals are provided.