Electrocatalytic reduction of CO₂ reduction reaction(CO₂RR) to high energy density fuel and high value-added carbon products under mild conditions is an extremely promising way for reduction of the CO₂ concentration in atmosphere and storage of the intermittent renewable energy, as well as for carbon neutralization. The design and development of low-cost high-performance catalysts with high activity, high selectivity, high stability and significant suppress of hydrogen evolution reaction(HER) is the key to the CO₂RR research. On the other hand, single atomic catalysts(SACs), due to their unique electronic and geometric structures, exhibit unusual catalytic activity for many important chemical reactions, such as CO oxidation, hydrogenation, OER, ORR, HER, etc., and have attracted extensive attention. Inspired by the profound progress, very recently, N-doped porous carbon support transition metal single atomic materials(M-N-C) have been employed in CO₂RR research. The results manifest that M-N-C catalytic materials have exciting prospects for CO₂RR, and are expected to be a substitute for precious metal(Au, Ag) catalysts for CO₂ reduction in electrolyte aqueous media. This review is focused on fabrications, electrocatalytic performance and MN_x active sites of M-N-C SACs used in electrochemical CO₂RR. Finally, the problems remaining to be solved are summarized, and future research aspects and new ideas are prospected.