The converse piezoelectric effect transforms the electricity into the mechanical motion. By connecting several energy harvesters in series circuit, the inverse piezoelectric effect will change the motion state of each energy harvester, thus influencing the performance of the entire energy harvesting system. Based on the electromechanical coupling model of two series systems of energy harvesters, the influence of the converse piezoelectric effect on the system dynamics and energy harvesting efficiency is analyzed by numerical simulation. The results show that the motion of each harvester is periodic provided that the motions of all the harvesters in the system are periodic, and the best performance will be achieved under the circumstance that all the harvesters are excited with larger amplitude. When the motion of one harvester is chaotic, the motions of other harvesters are either chaotic or pseudoperiodic motion, and the performance of the system is affected to some different extents. The parameter of the series circuit has significant impacts on the performance of the system.