To reduce the edge effect of low energy outside the waist radius of a Gaussian beam when high-power laser equipment is operating and avoid the problems of edge and lap marks, it is necessary to design effective beam shaping. First, to reduce the complexity of the system and improve the utilization of the laser energy, a high-power Gaussian laser light source(average optical power of 500 W, pulse widths in 130-160 ns, wavelength of 1 064 nm, and power regulation range of 10%-100%) was optimized using the Galileo aspheric lens shaping system.Second, through the law of conservation of energy, the mapping relationship between incident and emitted light was obtained, and the structural parameters and aspheric coefficients of the system were optimized and simulated using optical software. The output energy uniformity of the flat-top beam at ejection distances of 20,25, and 30 mm was calculated. The results show that the energy uniformity of the flat-top region is greater than 78.0% when the focal depth of the system is between 20 and 30 mm. A laser cleaning experiment is conducted using a rusted low-carbon steel plate. The interaction between laser and material is uniform in the area of spot action, proving that the design can meet the requirements of high-power laser environments.