The invention belongs to the field of application of building information models and particularly relates to a tower crane automatic model selection and optimization system and method based on a BIM (Building Information Modeling) technology. The tower crane automatic model selection and optimization method is carried out in a steel structure engineering construction site, and comprises the following steps: step 1: primarily determining a segmentation scheme of a steel structure according to a BIM model, counting weight of each member, automatically forming a database of each member and adding the database into a third-party BIM platform; and step 2: according to the BIM model of the construction site, determining a space position relation between an installation position of a steel member to be hoisted and a field tower crane, and automatically adding the space relation into the member database according to member numbers. By adopting the tower crane automatic model selection and optimization system and method based on the BIM technology, problems that the large-size and complicated-structure steel structure segmentation scheme depend too much on experiences and is in lack of refined and scientific optimization and improvement measures are solved.