Electrochemical CO2 reduction reaction（e-CO2RR） is a promising and facile method to achieve carbon-neutral economy and sustainable development due its simple device and capability to consume renewable energy to produce high value-added chemicals. However， e-CO2RR suffers from low selectivity and low current density because of its sluggish kinetics and the weak activity of the catalysts. Hence， single-atom catalysts are one of the most ideal materials for e-CO2RR by virtue of its maximum atom utilization and well-defined catalytic active sites. Single atoms derived from transition metal and main group metal are comprehensively reviewed. Heteroatom coordination， dual-atom site， metal-support interactions， spatial confinement and molecular bridging to tailor the microenvironment of single atom to realize a better catalytic performance are also included. Single-atom catalysts extremely accelerate electrocatalytic CO2 reduction kinetics， which is ascribed to its unique electronic structure and enormous intrinsic highly active sites， indicating its state-of-the-art merits and broad application prospects. Reductive products that involve multi-electrons are desired for single-atom catalysts. Finally， research trends and hotspots in this field are also discussed.
