In order to study the aeroacoustic characteristics of the new distributed tail rotor， the method used for the calculation of distributed ducted tail rotor aerodynamic and acoustic is established based on the sliding mesh method and penetrable surface. The Reynolds-averaged Navier-Stokes is used as the govern equation. The second order Roe scheme is used for spatial dispersion. The implicit LU-SGS scheme is applied to the pseudo-time marching. The S-A turbulence model is selected. The FW-H equation is used to calculate the noise. By the established method， the aerodynamic and acoustic characteristics of traditional tail rotor and distributed ducted tail rotor are calculated. The results indicated that compared with the traditional tail rotor， for the typical radiation direction， namely the tip-path-plane， the noise amplitude of distributed ducted tail rotor is reduced by 5—6 dB under the same aerodynamics， and with the decrease of rotor speed， the noise amplitude is decreased further.