In　the　present　work,　a　new　reflux　condensation　route　has　been　developed　for　synthesizing　a　Zn2SnO4　film,　which　was　first　used　as　a　compact　layer　in　a　perovskite　solar　cell　(PSC)　and　achieved　an　efficiency　of　20.1%.　The　high　efficiency　of　PSC　could　be　contributed　to　the　following:　(i)　as　a　compact　layer　in　a　PSC,　Zn2SnO4　exhibits　high　electron　mobility　and　has　an　appropriate　energy　band　structure,　resulting　in　the　efficient　extraction　of　carriers　and　transport　of　electrons;　(ii)　the　surface　of　the　FTO　substrate　is　completely　covered　by　a　Zn2SnO4　compact　layer,　and　the　direct　contact　between　a　perovskite　layer　and　FTO　is　prevented,　leading　to　a　significantly　efficiently　suppression　of　charge　recombination.　Consequently,　the　cell　consisting　of　a　Zn2SnO4　compact　layer　exhibits　excellent　photovoltaic　performance.