The invention belongs to the field of flexible forming of skull repairing bodies, and discloses a flexible forming device and a forming method of an amorphous alloy skull repairing body. The device comprises clamping units and a forming unit, wherein the clamping units are symmetrically arranged on the side surfaces of the forming unit; the forming unit comprises a tool head and laser devices; themultiple laser devices are uniformly arranged on the upper end of the tool head in the peripheral direction and are used for heating a to-be-machined zone before the to-be-machined zone below the tool head is machined by the tool head, so that a amorphous alloy plate of the to-be- machined zone is located in a supercooling liquid phase zone between a glass-transition temperature and an initial crystallization temperature; and the tool head rolls and forms the to-be-machined amorphous alloy plate along a preset trajectory layer by layer, so that flexible forming of the to-be-machined amorphousalloy plate is realized. Through the flexible forming device and the forming method, the biological compatibility of the obtained skull repairing body is good; bouncing of the repairing body is avoided; and the success rate of skull repairing surgery is improved.