A preconditioning method has been incorporated on unstructured meshes for analysis of incompressible inviscid flows. The Weiss-Smith`s preconditioning method is adopted for the present study. An implicit time-integration method and the Roe scheme is used for the computations. A dual time-stepping procedure is also applied for unsteady time-accurate incompressible flows. The method is shown to provide accurate solution and good convergence for steady-state low Mach number. Time-accurate solution of unsteady inviscid flow is also well demonstrated.