The invention belongs to the related technical field of component forming manufacturing, and discloses an electromagnetic gradual flexible composite forming method. The electromagnetic gradual flexible composite forming method comprises the following steps: providing an electromagnetic forming device, wherein the electromagnetic forming device comprises a discharge assembly, a multi-point supporting mould and four hydraulic cylinders, and the mould surface of the multi-point supporting mould consists of multiple discrete basic bodies; adjusting the basic bodies to form a top mould surface, and moving the hydraulic cylinders to tightly press a plate component; gradually moving a discharge coil along the top mould surface, gradually discharging the discharge assembly along with movement of the discharge coil, and gradually moving the plate component towards a direction away from the discharge coil till the plate component is fitted with the top mould surface; readjusting the heights of the basic bodies to form a new top mould surface, and reclamping the plate component; re-moving the discharge coil, and gradually discharging the discharge assembly till the plate component is fitted with the new top mould surface; repeating the steps till the plate component has a target shape. By the electromagnetic gradual flexible composite forming method, wrinkling is avoided, the thinning amount and the resilience are reduced, and uniform deformation of the plate component is achieved.