The utility model provides an independent opposite cutter type 3D multifunctional CNC engraving machine which has functions such as cylinder surface engraving, 3D engraving and plane engraving, and is high in engraving precision and work efficiency. A left standing column and a right standing column are movably connected to a lathe through a left guide rail and a right guide rail. Y-direction drive devices are disposed among the left standing column, the right standing column and the lathe. A gantry is disposed above the left standing column and the right standing column. A plurality of U shaft clamping devices are disposed on the lathe below the gantry. A left inner guide rail and a right inner guide rail are disposed on the inner side of the lathe. An ejector pin support plate is movably disposed between the left inner guide rail and the right inner guide rail. A left locking device is disposed between the left inner guide rail and the ejector pin support plate. A right locking device is disposed between the right inner guide rail and the ejector pin support plate. A plurality of ejector pins are disposed on the ejector pin support plate. A plurality of engraving heads connected through X-direction connecting rods are movably disposed on the gantry through an X-direction vertical guide rail and an X-direction horizontal guide rail. The engraving machine further comprises an X-direction drive device connected to the engraving heads. Each engraving head is of an independent Z-direction up-down structure.