The present application relates to the technical field of 3D printing apparatus, and discloses an electron beam melting and laser milling composite 3D printing apparatus which comprises a base, in which a powder spreading structure configured for spreading metal powders onto the machining platform is arranged on the base, an electron beam emitting structure and a laser milling head are arranged above the machining platform, the electron beam emitting structure is configured for emitting an electron beam to melt the metal powder layer to form a single-layer or multi-layer approximate body, and the laser milling head is configured for emitting a laser beam to mill the single-layer or multi-layer approximate body.