The invention discloses a method for accurately machining reinforcing steel bars based on BIM reinforcing steel bar shapes and parameters, and belongs to the technical field of reinforcing steel bar digital machining. The method comprises the following steps that 1, BIM modeling software is used for establishing a standardized BIM structure model according to a drawing; 2, a parameterized reinforcement model is arranged in the structural model according to a design drawing and a standard specification, and whether the reinforcement model has an error or not and the reasonability of the reinforcement model are analyzed; 3, after statistics is performed on design information, reinforcing steel bar shapes and specific parameters in all the reinforcing steel bar models, standardized reinforcing steel bar machining data are exported and transmitted to a machining management center; 4, the machining management center arranges an intelligent steel bar machining tool to automatically machine reinforcing steel bars after intelligent analysis and combination; and 5, the reinforcing steel bar processing finished products are intelligently packaged, stored into a warehouse, and intelligently dispatched. According to the invention, centralized and intelligent processing of the reinforcing steel bars can be realized, finally unattended processing of the reinforcing steel bars is realized, manpower and time are saved, and the working efficiency is improved.