Abstract: A disturbance vortex method for simulating unsteady rotor/stator interaction in turbomachinery is presented in this paper.The algorithm takes the result from time-averaged,steady solution as input,which can give an initial description of the unsteady disturbance flow field.To calculate the unsteady response to these disturbances,the Lagrangian vortex method is used to capture the convective process of the disturbance vortex.The deterministic vortex scheme is adopted to approximate the viscous diffusion process.The numerical simulation result of two-dimensional,viscous flow for a high loading transonic compressor with a pitch ratio of 1 74 shows that the method has an excellent ability for convergence and a fast convergent speed.The chopping,migrating process of rotor wake and other vortices,the influence of unsteadiness on incidence and decaying characteristic of the unsteady pressure first harmonic amplitude are included in this paper.