Abstract: The flavor of soy sauce is one of the key factor to determine its quality, but the formation mechanism of flavor is complex. The flavor is difficult to control. The formation mechanism of soy sauce flavor from different sources are analyzed, such as protein degradation, starch saccharification, fat hydrolysis and microbial species metabolism. The separation and identification techniques for volatile and non-volatile flavor substances in soy sauce are summarized, such as solvent direct extraction, purge and trap, solid-phase microextraction, electronic nose and electronic tongue. The theoretical basis and guidance for soy sauce processing technology and detection of volatile and non-volatile flavor compounds are provided.