Abstract: The principle of visualization techniques on noise sources identification(NSI) is des-cribed after a brief review of some traditional and signal processing based methods.The pressure signal is first acquired using a microphone array,and used to reconstruct the 3-D sound field with some reconstruction algorithms.The reconstructed sound field is then shown graphically so that the main noise sources can be "seen" with eyes.The techniques are categorized in terms of noise signal acquiring methods,reconstruction algorithms,and display modes.Three commonly used reconstruction methods,the Fourier methods,Helmholtz-Kirchhoff equation based methods,and the equivalent source method,are investigated and compared in detail.Focus is given to the last method with some currently existing difficulties presented.Finally,a solution to the visualiz-ation application for NSI is proposed.