This research attempts to explore the connotation of Human Flesh Search and the mass collaboration to realize the process of Human Flesh Search through analyzing the platform, participants, and ways to achieve the searching goal. The research examines previous definitions related to Human Flesh Search and mass collaboration in different environments through the methods of participant observation and in-depth interview. Ultimately, the research finds that Human Flesh Search engine is different from search engine and the nature of Human Flesh Search is that the answers and information are supplied by people’s power, specially netizens' participation and interaction in person, other than computer techniques. The Human Flesh Search is realized by the collaboration among different participants, including initiators, onlookers, informants, moderators, networking company, through the mass collaboration in the internet environment (online), in reality environment (offline) and between the online and offline environment. Keywords: human flesh search, search engine, mass collaboration