Participatory Research is an integrated activity that combines social investigation, educational work and action. It is different from the standard social science research methods: the fundamental principle of participatory research is that the researched are as much a part of the process as the researcher. Participatory Research is quite different from Participant Observation: the former aims to change the object of the study, while the latter abstains from affecting the environment. In adult education, the methods which were similar to the participatory research method have been taken for more than half a century throughout the world. In the United States, the Highlander Research and Education Center has been leading this field and has practiced various participatory research projects. This paper focuses on one of the Highlander's participatory research projects and seeks its possibility as a tool of empowerment of the people and transformative education. First, its history and theory are examined. Secondly, its world network is summerized. Thirdly, the participatory research project lead by Highlander is shown as an example of empowerment education. Finally, its new development and possibility are looked for.