Abstract: Self-powered system is a system that can sustainably operate without an external power supply for sensing，detection，data processing and data transmission. Nanogenerators （NG）were first developed for self-powered systems based on piezoelectric effect and triboelectrification effect for converting tiny mechanical energy into electricity，which have applications in internet of things，environmental/infrastructural monitoring，medical science，environmental science and security. NGs have three major application fields：micro/nano-power source，self-powered sensors and blue energy. We will present the applications of the NGs for harvesting body motion energy that will be used for medical science and bioengineering.