To address the challenge of removing epoxy primer from steel surfaces using a square flat-top pulsed laser,a numerical model of the laser paint removal process was developed with finite element software.Based on the heat conduction equation and thermal ablation theory,the paint removal performance of a Gaussian beam was compared with that of a square flat-top laser.The influence of spot length and spot overlap rate on the effectiveness of square flat-top laser paint removal was also investigated.The results indicate that the square flat-top beam offers higher energy utilization and produces cleaner ablation edges compared to the Gaussian beam,making it more suitable for large-area paint removal.At a laser power of 60 W and a repetition rate of 100 kHz,the maximum ablation depth increases with higher spot overlap rates,while the width of the heat-affected zone decreases.Both the maximum ablation depth and the heat-affected zone width decrease as the spot length increases. Under the parameters of 30% spot overlap and a spot length of 100 μm,the epoxy primer is effectively removed with minimal surface roughness.The findings of this study can serve as a useful reference for the application of square flat-top lasers in material processing.