Abstract: In order to achieve the accurate identification of the weak acoustic insulation areas of a car dash panel, a deconvolution approach to the mapping of acoustic sources (DAMAS) based on fast Fourier transform (FFT) and orthogonal matching pursuit (OMP) is proposed in this paper, which is named as FFT-OMP-DAMAS for short. Its core is to utilize the orthogonal matching pursuit based on the source sparse distribution assumption to solve the deconvolution problem, and further combine the Fourier transform and the spatial shift invariant assumption of the point spread function (PSF) to reduce the computational dimension. In this paper, the delay and sum (DAS), DAMAS and FFT-OMP-DAMAS beamforming methods are used to identify the weak acoustic insulation areas of a car dash panel in the reverberation chamber-anechoic chamber. The results show that the FFT-OMP-DAMAS beamforming can effectively suppress side lobes and spurious sources, and reduce the width of main lobe, so as to accurately identify the weak acoustic insulation areas of a car dash panel. In addition, compared with the traditional DAMAS method, the FFT-OMP-DAMAS method proposed in this paper can obtain clearer imaging results and significantly improve the computational efficiency.