To evaluate the effect of temperature on the mechanical properties of Ti6Al4V pulsed laser beam welding (LBW) joint, the mechanical properties are tested by tensile and fatigue tests under different temperature with comparison method, and the microstructure characteristic and fracture morphology are observed by optical microscope (OM) and scanning electron microscope (SEM). The results show that the tensile strength and the fatigue life of the LBW joints and the base metal specimens decline significantly as the temperature rises, the tensile strength of the base metal and the LBW joint under 300 ℃ are reduced by 26.2% and 31.6%, respectively, and the fatigue life of the base metal and the LBW joint under 300 ℃ are reduced by 83.6% and 77.8%, respectively. The microstructure observation after the fatigue fracture shows that the fatigue damage is concentrated in the fusion zone, and with the increase of temperature, the deformation on the surface of all the specimens increases, inducing the reduction of the fatigue life. The research result provides reference for the improvement of the lifetime and application safety of titanium alloys.