The invention discloses a BIM-based wallboard component reinforcing steel bar splicing system and method. Reinforcing steel bar machining information of a component to be machined is obtained througha logistics conveying device, needed reinforcing steel bar parts are conveyed from a preset storage position to a preset splicing stock position, a splicing control device obtains a BIM building design model, BIM set positions of the reinforcing steel bar parts in the component to be machined are analyzed, a splicing executing device is driven to grab the reinforcing steel bar parts to the BIM setpositions, and positioning splicing is carried out on a preset bench formwork. The problem of wallboard reinforcing steel bar splicing is solved, the manual intervention amount in the whole implementation process is extremely small, the machining efficiency of wallboard reinforcing steel bar cages is greatly improved, and the development tendency of industrial building is met.