CO2　reduction　reaction　(CO2RR)　provides　a　promising　strategy　for　sustainable　carbon　fixation　by　converting　CO2　into　value-added　fuels　and　chemicals.　In　recent　years,　considerable　efforts　are　focused　on　the　development　of　transition-metal　(TM)-based　catalysts　for　the　selectively　electrochemical　CO2　reduction　reaction　(ECO2RR).　Co-based　catalysts　emerge　as　one　of　the　most　promising　electrocatalysts　with　high　Faradaic　efficiency,　current　density,　and　low　overpotential,　exhibiting　excellent　catalytic　performance　toward　ECO2RR　for　CO　and　HCOOH　productions　that　are　economically　viable.　The　intrinsic　contribution　of　Co　and　the　synergistic　effects　in　Co-hybrid　catalysts　play　essential　roles　for　future　commercial　productions　by　ECO2RR.　This　review　summarizes　the　rational　design　of　Co-based　catalysts　for　ECO2RR,　including　molecular,　single-metal-site,　and　oxide-derived　catalysts,　along　with　the　nanostructure　engineering　techniques　to　highlight　the　distribution　of　the　ECO2RR　products　by　Co-based　catalysts.　The　density　functional　theory　(DFT)　simulations　and　advanced　in　situ　characterizations　contribute　to　interpreting　the　synergies　between　Co　and　other　materials　for　the　enhanced　product　selectivity　and　catalytic　activity.　Challenges　and　outlook　concerning　the　catalyst　design　and　reaction　mechanism,　including　the　upgrading　of　reaction　systems　of　Co-based　catalysts　for　ECO2RR,　are　also　discussed.