Abstract A novel Rh 1 Co single‐atom alloy (SAA) catalyst, in which Rh species are atomically dispersed on Co nanoparticles that are anchored by N‐doped carbon (N‐C) matrix for hydroformylation of olefins. The Rh 1 Co SAA/N‐C catalyst exhibits high activity towards the hydroformylation of 1‐hexene, achieving both nearly 100% conversion and selectivity as well as good cycle stability. It also shows extremely wide substrate generality for at least 17 different types of olefins. A synergistic catalytic mechanism of the Rh 1 Co SAA/N‐C catalyst was discovered that H 2 is dissociated on Co sites and Co‐H species are facilitated to be generated, CO is also adsorbed and inserted on Co sites that promote the C‐C coupling, while the Rh‐Co dual sites are beneficial to the co‐adsorption of 1‐hexene. Theoretical calculations reveal the Rh 1 Co SAA/N‐C catalyst shows a lower rate‐determining energy barrier of CO insertion due to the optimized charge distribution of the precursor of CO insertion at Co sites.