Abstract: A dynamic nonlinear analysis was performed to study the influence of a construction joint on the aseismic behavior of a regular reinforced concrete (RC) frame structures in 7, 8 and 9 earthquake intensity regions separately. Two numerical models for the same frame structure were built, one included a construction joint and another excluded it. The factors such as the maximum vertex displacement, story drift angle, the distribution of plastic hinge, and the reaction of critical members were analyzed. The results show that a construction joint has little effect to a frame structure when it is elastic under a frequent earthquake. However, the effect becomes significant once the frame is in the plastic stage under a rare earthquake. The maximum lateral displacement and story drift angle increased, and plastic hinges turned to be diagonal at the end of columns. The influence of a construction joint on the seismic behavior of a RC frame structure should not be ignored under large earthquakes.