Abstract: Lamb wave, as a commonly used guided wave in structure detection, is characteristic of long propagation distance and high capability, but its multi-mode and dispersion effect reduces its temporal and spatial resolutions for its application, to some extent. A Lamb wave imaging processing method based on compressed sensing is proposed, which needs to construct a reasonable dictionary to match the reflected Lamb wave signal. Firstly, MATLAB numerical simulation was used to obtain single-mode signals with different travel distances to build a single-mode modal dictionary; then the single-mode modality was selected by compressing the matrix. Similarly, a non-dispersion dictionary was built up, and a single-mode signal with no dispersion was obtained.