Abstract: TA19 titanium alloy was joined by inertial friction welding. Mechanical properties of welding joints at different welding parameters were evaluated by room temperature tensile, high temperature tensile and microhardness tests. Microstructures of an optimized welding joint were analyzed. The results showed that TA19 titanium alloy had good weldability by inertia friction welding, while high-quality joints could be obtained at reasonable welding parameters. The microhardness of the welding zone was the highest. The microhardness gradually decreased distancing away from the welding zone. The welding zone was characterized by the typical dynamic recrystallized microstructures composed of small number of α phases and α′ martensite along the grain boundary of β phase. Thermo-mechanical affected zone was composed of the deformed primary α phases and α′ martensite. The microstructures in heat affected zone was similar to those in the base metal, only containing partial plate strip β phases and plate strip secondary α phases in crossing distribution.