The invention provides a gantry type double-head computer numerical control (CNC) milling machine for hub machining, comprising a bedplate and characterized in that two symmetrical gantry racks are arranged on the bedplate; vertical milling head devices are installed at the reverse positions of the two gantry racks, and longitudinal guide rails are arranged on the bedplate, and run through the two gantry racks; two workbenches are installed on the longitudinal guide rails movably, and fixtures able to clamp workpiece are arranged on the workbenches; a workpiece delivery device is arranged between the two gantry racks, and comprises a clamping device and a lifting device able to drive the clamping device to move upward or downward; the workpiece on the left workbench can be delivered to the right workbench through transition of the workpiece delivery device. The CNC milling machine provided by the invention is mainly used for the hub machining, and the workpiece can be clamped automatically by the fixtures. The workpiece roughly machined is delivered to the right workbench through the workpiece delivery device for fine machining. The CNC milling machine provided by the invention has the advantages of high level of automation and small occupied area.