Flexible devices have been drawn a great attention as next-generation electronic devices. Especially for flexible and wearable system, the challenge to achieve such systems are the development of functional and flexible new materials and unique integration method of conventional devices into flexible ones including high performances. Nevertheless, such nanosystem also requires a power source to make the entire package small, sustainable and even long lasting. In this regards, harvesting energy from the environment is a choice for powering nanosystems. As for the goal, it is desired to explore flexible and wearable devices for scavenging energy around our surroundings, thus it can supply the power to nanosensor system without consuming much battery or to supporting battery life. Here, we will present some approaches for converting mechanical energy into electric energy using piezoelectric or triboelectric effects. This technology may make it possible to harvest energy from certain mechanical movements or human activity. Moreover, self-powered nano-sensor systems have been fabricated by combining the energy harvesting technology which ensures its compatibility and perspective. The presentation will be continuously dedicated to recent developments and improvements of energy harvesting technology towards self-powered nano-systems such as mobile electronics and wearable healthcare.