45 steel valve body in extruded casting was adopted in designing combined mould, in which core and punch adopts H13 tool steel, and sleeve and poisoned structure uses 45# steel or 40Cr steel. And special extruded machine with maximum extruded force of 1 500 kN and closed forces of 2 000 kN is used with punch velocity of 0.30⁰.35 m/s. Drawing-mould declination is 2°,2°and 0.5°for up-punch, down-punch and side-punch, respectively. And the down-punch directly pushes the castings for pushing ways, where fit clearance between punch and the mould is 0.16⁰.2 mm. The position of the die subjected to higher thermal stress has been cooled by tube-cooling combining with inserted-pipe cooling. Four overflow slots on cross-position of parting surface have been set to ensure the accuracy of the casting in height direction. To improve fusion-resistant ability of the die, the coating with thickness of 0.2 0.5 mm using self-developed siliceous earth coating is conducted.