Gas flow in an axisymmetric interrupter was calculated by a weighed residual finite element method. In the scheme Taloy series expansions for time discretization and Galerkin method for spatial discretization were applied. The artificial viscosity was introduced into the governing equation to surpass the numeri -cal oscillation.The equation was solved by the lumped mass method . The agre -ement between the numerical results and the thereotical analysis shows the effec-tiveness of the numerical method.