Abstract: For a complicated thin-wall titanium alloy conical cylinder, composite mold forming process of ceramic core and machined graphite mold was designed.The ceramic core is used for complicate cavity forming to improve the dimensional accuracy and surface quality of the casting.The graphite mold is made by machining graphite to set the gating and riser system conveniently.Titanium alloy conical cylinder casting prepared by using the composite mold has high internal quality and surface quality.