Abstract: Back-extrusion can ensure the streamline of forgings.The back-extrusion process route for TC4 titanium alloy large fan pressurized class drum forging of the certain type of an engine was worked out.Reasonable size and forging parameters of middle blank for die forging were obtained through finite element numerical simulation.The room temperature tension, high temperature tension, impact, fracture toughness and other mechanical properties of the drum forged on 400MN hydraulic machine are excellent, which can obtain the double state microstructure with equiaxial primary α phase content of 35%-40%.