Today, with development of technology and reduction of natural energy sources, it is more than ever necessary to recycle lost energy in nature. On the other hand, the increased need for portable and lightweight electronic devices cause to replace battery in these devices with another energy source. Using battery in the electronic devices like wireless sensors, medical-electronic equipment and tire pressure control systems cause some problems like high weight, periodic replacement and also environmental pollution. An idea for solving these problems, is harvesting environmental wasted energy and conversing it to electrical energy. The aim of this study is designing and constructing a system to harvest wasted mechanical energy in human body movements and convert it to electrical power. For this purpose, one of the simplest piezoelectric energy harvesters composed of a cantilever beam with piezoelectric layers on two sides of the beam was analytically studied. The electormechanical relations for its motion under base excitation was extracted. For using energy harverster systems in optimaized conditions, researchers have tried to expand the frequency bandwith in recent years. To solve the challenge of increasing the frequency bandwidth and improve the performance of the harvester a nonlinear piezoelectric energy harvester composed of a cantilever beam with piezoelectric layers and two curved shape supports was designed. First superiority of the proposed system to a linear one was shown. In the next step, some tests were performed to obtain the acceleration of walking at an approximate speed of 4 km/h and the acceleration signals were recorded. Since the fundamental frequency of measured signal was concentrated in the frequencies below 15 Hz, a linear harvester with a first natural frequency of less than 15 Hz was designed. Then using this linear system, a nonlinear energy harvester composed of curved supports was designed. This nonlinear energy harvester was optimized for geometry of curved supports and electrical resistivity to harvest the maximum energy at approximate speed of 4 km/h. After constructing the optimized nonlinear system, the energy harvester was tested under the base excitation at the acceleration of 7 m/s 2 , 10 m/s 2 and 12 m/s 2 by a shaker. The results were validated with the results of the finite element modeling in Ansys. Finally to measure the energy harvesting from walking, the constructed energy harvester was connected to a person’s leg and an accelerometer was attached to the other leg. Energy harvesting from the system was measured for 7 speeds using treadmill and the average leg acceleration and the output voltage were recorded for each test. The results of these tests in the speed of 4 km/h was in a good correlation with the results of finite element modeling at this speed. Keywords: Piezoelectric effect, energy harvesting, piezoelectric layer, piezoelectric patch, base excitation