In order to explore the ablation characteristics of ultrafast lasers on metal materials,TC4 was processed by femtosecond pulsed laser to study the surface morphology of TC4 after processing,and the mechanism of femtosecond laser processing of metals was analyzed.When the laser energy density was 8.05 J/cm2,the surface morphology of the material at different scanning speeds was observed by white light interference and scanning electron microscopy.As the scanning speed decreases,the surface fringes become deeper,the size of the secondary micro-nano bump above the stripe increases,the roughness increases,and the classic low spatial frequency fringes appear on the side of the stripe.The formation mechanism of various morphologies is analyzed from the characteristics of Gaussian beam and the overlap ratio of the spot.The energy density at the center of the Gaussian beam is high,the bulge is formed above the stripes,and the classic stripes are formed on the sides.When the spot overlap rate is larger,the unit area is within the greater the energy density,the larger the surface microstructure size.