Based on the Beijing No.1 Experimental School, this paper studies the application strategy for BIM during the initial design phase of public building. Moreover, the paper explores how to verify the periodical design result of architecture, structure, and mechatronic, etc., with BIM modeling and how to establish balance between the architectural effects and economy. From the work above, this paper could assistant effectively decision-making for owner and designer, and further promote the quality of design. Based on this, the practical experience of design-dominated application of BIM is summed up, which can provide reference for the BIM application during the initial design phase of public building.