The safety performance of pedestrian and roadway dimensional-dividing buildings under seismic excitations are analysed.Considering the large displacement of the isolator bearing during earthquake,the gravity force becomes the dominant forces because of the accumulated permanent deformations in the building,which results in the structure collapse due to lateral instability.A model is established based on an inelastic time history analysis to consider P - △ effects in multi-degreeof-freedom.A safety criterion of the system is defined.The influence of the stiffness of an independent column is revealed and compared with the influence of the shear force of the independent column to analyze the safety of the structures.Numerical results show that the special structure of pedestrian and roadway dimensional-dividing buildings can reduce the risk of the building in earthquake.The suitable section and height of the independent column greatly affect the building safety.