Abstract: Based on the Lighthill's acoustic equation, the boundary element method (BEM) combined with the computational fluid dynamics (CFD) was utilized to achieve the distribution of aerodynamic dipole source on high-speed train surface. The strength and distribution of the aerodynamic dipole source under different train speeds were investigated, and train's external aerodynamic acoustic field based on the aerodynamic dipole source was analyzed by a numerical simulation. The research results show that when a train runs at 270 km/h and the frequency is 2.5 kHz, main aerodynamics noise source with a sound pressure level over 90 dB is located near its bogies, and the maximal sound pressure level is approximately 97 dB.