Abstract: Being taken TC4 thin-walled titanium alloy as the research object,the laser welding process research and the forming control of laser welding were carried out. The influence of welding parameters such as welding process protection,laser energy,defocusing amount and welding angle on weld appearance were studied. The research results show that the laser process window of TC4 thin-walled titanium alloy at low welding speed is narrow,which requires the precise energy input control. The high-speed laser welding of the TC4 thin plate structure effectively expands the process window. Increasing the amount of laser defocusing amount can also increase the melting width,but it is necessary to appropriately control the ratio of laser power to the defocusing amount about 100 ～ 140 W/mm. It is significant to improve laser input during laser large-angle oblique welding process to ensure well wald appearance,due to the scattering phenomenon.