The invention discloses a large structural member sling system and a hoisting method. The sling system comprises at least one group of sling components, wherein each group of the sling components comprises two annular lifting ropes, and each lifting rope comprises a plurality of wires, a lifting hook and four lifting lugs; each wire is made from polyethylene plastic materials with ultra-high molecular weight; each lifting hook comprising four hooks; the four lifting lugs are arranged on a large structural member; when the large structural member is lifted, each annular lifting rope penetrates through two lifting lugs at one side of the large structural member; two parts, located between the two lifting lugs, of the lifting rope are hung on the two hooks, located at one side of the two corresponding lifting lugs, of the lifting hook separately. Compared with an existing hoisting method that steel wire ropes are directly wound the lifting hook, the hoisting method that annular steel wire ropes are directly hung on the lifting hook, and the hoisting method that the steel wire ropes are used for hoisting after the lifting hook is used for suspension aided by horizontal slings, the sling system has the advantages of easy hoisting, adjustment and leveling, and can be used for providing stable tensile force for the large structural member; and the hoisting stability and the hoisting efficiency are improved.