The invention discloses a bidirectional feeding multi-knife bending automatic alignment process method for a numerical control bending machine. According to the bidirectional feeding multi-knife bending automatic alignment process method for the numerical control bending machine, a multi-axis composite feeding device, a bending machine workbench and a numerical control system are provided. The process method comprises the following steps: S1, mounting one area-array camera at each of the left end and the right end of the bending machine workbench; S2, controlling by a numerical control systemto trigger the area-array camera to take photos, acquiring an image of a to-be-detected workpiece in real time, uploading and feeding back the image information to the numerical system, processing byimage detection software, displaying curve fitting result on a display and replacing artificial sample plate measuring; and S3, when a back half arc is bended, detecting the error of a bending line and machine tool line laser cluster on the workpiece in real time, controlling operation of the multi-axis composite feeding device and completing automatic positioning of the back half arc bending. Theartificial sample plate detection process is omitted, automatic positioning of the whole feeding process is realized, automatic acquisition of bending forming shape is completed and the industrial automation degree is high.