Abstract: By taking example of the 2D Navier-Stokes equations,a kind of improved version of the nonlinear Galerkin method of Marion-Temam type based on the new concept of the inertial manifold with delay(IMD) is presented,which is focused on overcoming the defect that the feasibility of the M-T type nonlinear Galerkin method heavily depended on the least solving scale.It is shown that the improved version can greatly reduce the feasible conditions as well as preserve the superiority of the former version.Therefore,the version obtained here is an applicable,high performance and stable algorithm.