In order to study the influence of the power gas with high temperature and high pressure on the titanium alloy light-weight gun barrel, taking certain type small-caliber titanium alloy light-weight gun barrel as studies object, a thermal-structure coupling model of gun barrel was established based on ANSYS platform. The direct coupling analysis is employed and the program was written based on ANSYS parameter design language. Temperature field and transient stress response of this gun barrel was calculated under the cyclic action of high-frequency dynamic thermal pulse and dynamic pressure pulse. And a series of experiments were carried out to test the simulation results. This study shows that the coupling effect of thermal pulse and pressure pulse are very obvious and material property of titanium alloy meets the requirement of the design of gun barrel. And the research results have important significance for the design and optimization of titanium alloy gun barrel.