The design of axial labyrinth seal usually uses the research results of rotating labyrinth seal for reference at present,however there are great differences in the internal fluid change forms of axial labyrinth seal.In order to investigate the flow field distribution and leakage characteristics of axial labyrinth seal,the toothed axial labyrinth seal structure used in the piston cylinder of a type of labyrinth compressor was studied.The 3D model for the axial labyrinth seal was established and the leakage characteristics of the labyrinth seal were analyzed by numerical simulation under the influence of fluid-structure coupling.Through the simulation analysis of the internal flow of the axial labyrinth seal,the change law of the internal fluid in the labyrinth channel was obtained.The results show that the design of the tooth structure of the axial labyrinth seal can effectively convert the fluid pressure energy into turbulent kinetic energy,and realize the seal through step-by-step energy loss.The maximum deformation of labyrinth seal structure occurs at the inlet,and the total deformation of the piston cylinder at the fluid outlet is reduced.The axial labyrinth seal structure was applied to the compressor for experimental test.It is shown that and the sealing performance between the cylinder and piston is good,which provides theoretical support for the structure design and application of axial labyrinth seal.