The noise generated by air-conditioner and the sound quality of air conditioner have been paid more attention to. The purpose of this dissertation is to reduce the noise generated by air conditioner and improve the quality of air conditioner through optimizing the structure of the air-conditon duct system. For this purpose, the CFD simulation and experimental investigation is given to the indoor unit and outdoor unit of air conditioners. The main contents include:1) The flow field and sound field were simulated with CFD software for the indoor unit of the air conditioner. The influence of the heat transfer on the flow field and sound field of the indoor unit was investigated. A transient 3D simulation was given to the air conditioner indoor unit with bevel blade cross-flow fan. The influence of the bevel blades on the flow field and sound field was also investigated.2) The flow field was simulated with CFD software for the outdoor unit of the air conditioner. The influence of the deflecting ring on the flow field and sound field of the outdoor unit was investigated and a new design (double contoured duct design) was mentioned to improve the flow field and sound field of the outdoor unit. The influence of the outlet louver on the flow field and sound field was also investigated. The influence of different oulet louvers (square, circular, equal steel wire diameter and different steel wire diameter)