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Time inversion multi-signal classification (TR-MUSIC) algorithm for ultrasonic imaging of defects in concrete structures can break the diffraction limit and realize super resolution imaging under the condition that the excitation frequency does not change and the detection distance is guaranteed； However, the disadvantage of this method is that it is easy to be disturbed by noise, and additional singular values are generated in the process of imaging dividing signal subspace and noise subspace, which affects the accuracy and accuracy of ultrasonic imaging； In order to further improve the quality and stability of TR-MUSIC algorithm in ultrasonic imaging and suppress the interference of noise on imaging, a noise processing method based on variable mode decomposition (VMD) was proposed；The variable mode component after VMD decomposition was determined by combining energy entropy and barycentric entropy to determine the noise component of signal spectrum divergence and uneven energy distribution. The noise components were processed by wavelet threshold denoising method, and the noise components and other components were processed by Savitzky-Golay filtering and reconstructed. Inversion imaging of the improved signal improves the distinction of the corresponding singular values of the signal subspace and noise subspace. Then, the imaging resolution is improved and the artifact problem caused by noise is suppressed by setting thresholds.