The invention provides a titanium alloy laser arc hybrid welding 45-degree welding gun welding gas protection dragging cover. The dragging cover comprises a dragging cover body, a gas sieve plate, a gas outlet plate, a gas inlet connecting pipe, a connecting clamp and a semicircular fixing seat, the dragging cover body comprises a top plate, a 45-degree fixing seat and a rear plate, the gas sieve plate is arranged in the dragging cover body, the gas outlet plate is arranged below the gas sieve plate, the gas inlet connecting pipe comprises a gas inlet pipe body and a sleeve shaft, and the connecting clamp comprises a connecting plate, a connecting clamp body and a fixing clamp. By means of the dragging cover, high-purity argon can be effectively and evenly injected into the titanium alloy welding surface, a titanium alloy welding seam is isolated from air, the gas protection problem during butt welding of titanium alloy laser-arc hybrid welding flat plates can be solved, a welding area is thoroughly protected, and the performance quality of a welding joint is improved.