Based on the computational fluid dynamics (CFD) method, the influence of new blade-tips with different anhedral angles on rotor blade-vortex interaction(BVI) noise in forward flight is researched. In order to get the detailed flowfield information for the rotor noise computation, a new CFD method is established based on the Navier-Stokes equations with Spalart-Allmaras turbulence model. The dual-time stepping method is employed to simulate the unsteady flow phenomenon, while the implicit LU-SGS scheme is applied to the pseudo-time marching. To further improve t he computational efficiency, a suitable parallel strategy is introduced in the developed code. Calculations on acoustics of helicopter rotor are conducted based on the Farassat 1A formula from FW-H equations, and the capability of this method is demonstrated by the comparisons of the numerical results with available experimental data. Based upon the method, the aeroacoustic characteristics of the rotor with different anhedral angles in oblique descent flight are analyzed, which demonstrate that the new blade tip with appropriate anhedral angles can reduce the rotor noise effectively, especially the BVI noise in oblique descent flight.