On the basis of analyzing the green aviation requirements, FAR noise standards, air frame noise sources, this paper discusses the state of the art of aero-acoustics techniques including CFD, wind tunnel test, flight test and noise reduction in details. The importance of aero-acoustics research on high-lift devices is indicated, and the future trend of high-lift devices aero-acoustics——the aerodynamic integrated aero-acoustics high-lift devices design,is clearly pointed out.