Abstract: Displacement-based seismic design of RC frames is based on the displacement shape of the RC frame,and multi-degree-of-freedom system is transformed into an effective single-degree-of-freedom system.Based on equivalent linearization,equivalent period is determined by using the elastic-plastic displacement response spectra,and then the structural members are designed.At the same time,target deformability of the beams and columns are obtained by decomposing the structure's storey drift.And the expected deformability of the structure can be guaranteed by appropriate locate the ratio of stirrup.This method could effectively control the seismic performance of the structure in different intensity earthquakes.