Based on experiments of CO2 laser welding to vehicle body, joint microstructure and mechanical property of specimen are analyzed. The deep punching performance of laser welding adopting Ar as protective gas is better than that acquired by adopting N2. Meanwhile the percentage of zinc in welding seam can be effectively controlled by the side protective gas blowing. Welding depth and width varying with laser power and speed of welding were also investigated. The result indicates that it does not appear some flaws, such as gas hole, crack and softening of heat affect zone (HAZ) in laser welding seam of tailor-welded blanks through optimizing technology parameters. The deep punching performance of tailor-welded blanks is of very high quality. Forming property of tailor-welded board depends on strength ratio and thickness ratio of two materials, welding line mainly locates at high strength galvanized steel sheet, the offset of welding line tends toward thin general steel.