The application of galvanized steel tailor-welded blanks not only improves the corrosion resistance property of a car, but also reduces vehicle weight while the intensity maintains the same. Compared with other welding technologies, laser welding has lots of advantages, such as a narrow welding line, a high strength joint and a small heat-affected zone. However, the gap between the plates can cause surface depression and intensity deficiency. After obtaining suitable parameters of side-blown shielding gas, orthogonal experiment is designed to have a research on laser power and welding speed′s influence on weld formation through tailored blank fiber laser welding. After that, metallurgical experiments, tensile tests and cupping tests are used to detect the performance, mechanical and deep stamping properties of the welding line. The result shows an optimum parameter when the laser power is 3 kW and the welding speed is 4 m/min. On the basis of optimal parameters obtained, a further study is made on gap′s influence on weld formation. The result shows that a nice welding line can be obtained when the gap is not more than 0.15 mm（about 11.1% of the plate thickness）.