Abstract: Metal single atom catalysts (SACs) have been attracting increasing attention in recent years owing to their incredible performance in several key catalytic reactions such as the oxygen reduction reaction and CO oxidation. The construction of well dispersed stable SACs can not only make it possible to understand the catalytic reactions on the atomic scale, but is also important for developing novel industrial catalysts. Recent efforts have been focused on dispersing metal SACs on carbon substrates rather than on metals or metal oxides for improved catalytic behavior. Especially, graphene-based materials have proven to be excellent candidates for supporting SACs due to their unique structural and electronic properties. Nevertheless, the anchoring mechanism between metal SACs and carbon substrates is not well understood. Here we review the many roles of carbon materials as the support of SACs and highlight the anchoring mechanism. We also propose some suggestions to improve the experimental and theoretical research methods to expand the number of applications and realize industrial applications.