The invention discloses a method for quickly assembling BIM exit and entrance model, which comprises the following steps: segmenting the whole exit and entrance model; positioning each segmented model; inputting corresponding size parameters for each model after positioning, and generating the corresponding model; after all the generated segmented model are assembled integrally, forming the overall exit and entrance model. The invention also discloses a system for quickly assembling the BIM exit and entrance model, which comprises a segmenting module, a positioning module, a generating module and an assembling module. By adopting the method and system for quickly assembling the BIM exit and entrance model, the standardization and modularization of the exit and entrance design are realized, which greatly reduces the design difficulty, reduces the design time and improves the work efficiency.