The invention provides a laser remanufacturing method for a metal structural part and belongs to the technical field of laser rapid forming. The laser remanufacturing method comprises the steps that an initial melting point is selected from any point at one end of a metal structural base material, laser cladding is conducted on a first line of circular ring of a first layer, and after finishing, a laser spot moves towards the other end of the metal structural base material by 1-2 mm along the inner side of the first circular ring, and laser cladding of a second line of circular ring is started; the laser cladding steps are conducted repeatedly until the amount of cladding lines is in direct proportion to the length of the structural part, and then machining is conducted; then the height of a laser head is increased by 1-2 mm, laser cladding is conducted on a second layer and a third layer; and finally the three laser cladding layers form a cladding layer of the metal structural part, the total thickness of the cladding layer is 3-5 mm. A cladding layer material is Co-based metal powder, laser cladding parameters used in the steps are consistent, laser power is 2000-3000 kw, and the diameter of each laser spot is 2-3 mm. The laser remanufacturing method has the advantages of corrosion resistance, abrasion resistance, high hardness and long service life.