Ring piezoelectric energy harvester (RPEH) suitable for the low voltage SoC system with advanced CMOS technology is designed, which consists of ring metal substrate, ring piezoelectric ceramic transducer (PZT), elastic matrix and mass. In order to analyze carefully the force-electric performance of RPEH, the finite element model is obtained through meshing the corresponding solid model and then used to simulate. Simulated results show the output voltage and the natural frequency can be significantly reduced by ring structure compared with the traditional cantilever PEH. RPEH with elastic matrix can obtain the wider frequency band and the larger voltage than one without elastic matrix.