Abstract: α and near-α titabium alloys are widely used and have good plasticity in welds. In the welding process of titanium alloy, the welding temperature field has a significant effect on the microstructure of the welded joint, and then affects the mechanical properties of the component. The butt welds of Ti-2Al-2.5Zr and Ti-4Al-2V titanium alloys were prepared by gas tungsten welding(GTAW). The temperature field simulation of the welding process and the microstructure characterization and grain orientation analysis of the weld section were carried out. The results show that the distribution of welding temperature field is more uniform, and the peack temperature increases gradually at different positations along the welding direction. There are differences in the microstructure and envolution of the weld heat affected zone(HAZ) and the fusion zone(FZ). From the HAZ to the FZ, the grain orientation transitions from disorder to order, and the crystals show a certain degree of variant selection. With the increase of the peak welding temperature, the grain orientation tends to be stable, and the trend of variant selection is more obvious.