Research on asymmetric A-D-A structured non-fullerene acceptors has lagged far behind the development of symmetric counterpart.In this contribution,by simply replacing one sulfur atom in indacenodithiophene unit with a selenium atom,an asymmetric building block SePT and a corresponding asymmetric non-fullerene acceptor SePT-IN have been developed.Asymmetric SePT-IN achieved a high efficiency of 10.20％ in organic solar cells when blended with PBT1-C,much higher than that of symmetric TPT-IN counterpart (8.91％).Our results demonstrated an effective heteroatom substitution strategy to develop asymmetric A-D-A structured non-fullerene acceptors.