Abstract: In this paper, the Disperse software is used to calculate the dispersion curves of shear-horizontal (SH) guided wave in a 3 mm thick aluminium sheet, an electromagnetic acoustic transducer (EMAT) with a center frequency of 0.22 MHz is developed to generate SH guided wave, and the experimental research on B-scan imaging detection of the straight cracks in the aluminium sheet is carried out. The synchrosqueezed wavelet transform (SWT) is used to de-noise the SH guided wave signal from the straight cracks. Experimental results show that SWT can remove the noise in the original guided wave signal, realize the guided wave mode separation and improve the quality of the B-scan image. The designed SH guided wave EMAT can effectively detect the artificial direct crack of 10 mm long, 1 mm wide and 2 mm deep in the 3 mm thick aluminum sheet specimens.