Abstract: Based on the systematic analysis on the design standards and design procedures of prefabricated buildings, and aiming at improving the prefabrication rate, this paper develops a design scheme of prefabricated constructions, and establishes an automatic calculation model prefabrication rate through the parametric design method applying BIM and Dynamo. The study in this paper organically integrates the prefabrication rate goals into the prefabricated construction, and proposes the selection of application proportion of prefabricated components under different prefabrication rates for reference through statistical analysis. In the end, a case study is given to verify the feasibility of this method in the optimization of prefabricated construction design scheme.