Abstract – MEMS (Microelectromechanical Systems) devices have found wide applications for Internet of Things (IoTs). For IoT applications, MEMS devices should be able to work continuously for a long time without losing power. As a result, low power design is necessary for IoT devices. It would be even better if they can harvest energy from surrounding environment and recharge its battery to maintain the working status of the device. In this poster, a MEMS piezoelectric vibration energy harvester with improved frequency response is reported. It utilizes piezoelectric material to convert the vibration picked up from surrounding environment into electrical voltage and use it to charge the battery. Piezoelectric energy harvesters (EHs) have maximum energy conversion efficiency when they work at resonant vibrational mode. Traditional EHs only have one resonant frequency, which limits the vibration energy it can harvest with maximum efficiency. In this project, we developed a MEMS piezoelectric energy harvester with multiple resonant frequencies. This leads to improved frequency response and enhance its energy conversion efficiency. The device is designed and simulated in COMSOL.