In order to detect the surface crack information of aluminum plate using laser array source, the physical process of the interaction between Rayleigh wave and surface crack of aluminum plate is simulated by finite element method (COMSOL) in this paper when the single-pulse line source and laser array source are acting separately. Based on the thermoelastic mechanism, finite element models are constructed for the excitation of Rayleigh waves on the surface of aluminum plate irradiated by single-pulse line source and laser array source respectively, and the results of both numerical simulation are compared. The physical processes of Rayleigh wave interaction with cracks at different depths on the surface of the aluminum plate are simulated numerically when the laser array source acts, and the signals obtained from laser array sources of each array element are compared; when laser array sources with different line half-widths act, the amplitude and spectra of Rayleigh wave obtained from the excitation of them are compared, and the detection depths of the Rayleigh waves obtained from the excitation of laser array sources with different line half-widths are studied. The findings indicate that the amplitude of the Rayleigh wave changes post-time modulation with an increase in the number of array elements, and the amplitude is proportional to the number of array elements from the laser array source, suggesting a cumulative effect on the Rayleigh wave amplitude. An increase in the half-width of the laser array source line results in an increase in the Rayleigh wave wavelength and an expanded range of crack depth detection.