Abstract: The mechanism of acoustic radiation from transition and turbulent boundary layer of an axisymmetricbody is analyzed,and the sound pressure spectrum of boundary layer radiation is predicted.It is shown that theacoustic radiation result from the transition and turbulent boundary layer,and the acoustic radiation from transitionis predominant at low frequency domain;turbulellt boundary layer has the decisive effect on acoustic radiation at highfrequency domain.The calculated values are in agreement with the experimeotal data very well.