Currently,pyrolysis as the most widely used method still has some key issues not well resolved for syn-thesis of carbon-supported single-atom catalysts(C-SACs),e.g.,the sintering of metal atoms at high tem-perature as well as the high cost and complicated preparations of precursors.In this report,molten salts are demonstrated to be marvellous medium for preparation of C-SACs by pyrolysis of small molecular precursors(ionic liquid).The ultrastrong polarity on one hand establishes robust interaction with precur-sor and enables better carbonization,resulting in largely enhanced yield.On the other hand,the aggre-gation of metal atoms is effectively refrained while no nanoparticle or cluster is formed.By this strategy,a C-SAC with atomically dispersed Fe-N4 sites and a high specific area over 2000 m2 g-1 is obtained,which illustrates high ORR activity in both acid and alkaline media.Moreover,this SAC exhibits superior methanol tolerance and stability after acid soaking at 85 ℃ for 48 h.It is believed that the molten-salts-assisted pyrolysis can be developed into a routine strategy as it not only can largely simply the synthesis of C-SACs,but also can be extended to prepare other types of SACs.