Abstract: The noise sources of engine are very complex and difficult to be identified by ear. The noise source identification technique using microphone array can provide an objective basis and guidance for engine noise control. Based on beamforming technique, the multi-dimensional source recognition method is studied and the recognition of multiple sources in different planes is simulated. The cross-layer method can get the stereo results of source positioning, and it can effectively reduce or remove the false projections on the recognition surface from the sources outside the recognition surface. Finally, for a certain engine product, the plane microphone array is used to collect the sound pressure signals from the top, front, left and right sides of the engine at different speeds, and the cross-spectrum matrix beamforming algorithm is used to obtain the sound source distribution image on each engine surface and at each speed. By the cross-layer method, the stereo distribution of the sound sources on the engine surface is obtained, and the sound sources are accurately located to the corresponding parts of the engine surface.