By applying 5 order accuracy WCNS (Weighted Compact Nonlinear Schemes) to simulate forced oscillation of NACA0012 aerofoil, some techniques of high accuracy method in unsteady simulation were studied, such as inner iteration capability, inner iteration parameters of “dual time stepping” method, and discretization accuracy of time derivatives of Euler equations. The results show that, these coefficients have a remarkable effect on computation accuracy and CPU time when WCNS scheme is applied to unsteady flow simulation.