In order to study the influence of the deformation of labyrinth teeth of nonmetallic thermoplastic materials on the sealing performance,the transient fluidsolid coupling numerical solution model of labyrinth seal leakage characteristic considering tooth deformation was established.The accuracy of numerical solution model was verified,and the mechanical properties and leakage characteristics of labyrinth seals with three kinds of materials,phenolphthalein poly (aryl ether ketone) (PEKC),polyether ether ketone (PEEK),poly (ether sulfone ketone) (PPESKca30) under different inlet and outlet pressure ratios were analyzed.The results show that the pressure at the top of the last tooth in the sealing flow field with tooth deformation considered is lower than that without considering tooth deformation under the same condition,and the velocity is just the opposite.Under different inlet and outlet pressure ratios,the sealing teeth are deformed under the action of airflow force,and the sealing radial clearance is increased,resulting in an increase in leakage from 6.6% to 30%.When the inlet and outlet pressure ratio is the same,the larger the elastic modulus of the material,the smaller the deformation of the sealing teeth,the better the sealing performance.Among the three materials studied,PPESKca30 has the least deformation and the least sealing leakage.The maximum deformation of seals occurs in the position of the tooth top,and the deformation is gradually decreased from the position of the tooth top to the direction of the tooth root.The maximum value of the equivalent stress of the seal is distributed in the position of the tooth root,and the equivalent stress is increased gradually from the position of the tooth top to the direction of the tooth root.