Aiming at the problem of increasing workload of the assembly integral construction design, this paper adopts BIM two development technology and puts forward the structure of the split system based on BIM technology. Through the BIM model of prefabricated concrete buildings, respectively establish corresponding node group selection and structure, according to the beam column intersection, in order to obtain the type and size of length, node specifications and precast beam. Finally, the automatic split function of the concrete beam in the whole building is realized.