Pyrochlore-type　(Ca,Ti)2(Nb,Ti)2O7　thin　films　have　been　grown　on　single-crystalline　LaAlO3　and　yttria-stabilized　zirconia　substrates　by　a　magnetron　sputtering　system.　Atomic-scale　interface　structure　and　growth　mode　of　the　(Ca,Ti)2(Nb,Ti)2O7　films　on　the　substrates　with　different　crystal　structures　have　been　investigated　by　advanced　electron　microscopy　techniques.　In　both　heterosystems,　the　film/substrate　orientation　relationship　of　[100](001)film//[100](001)substrate　has　been　determined.　In　the　heterosystem　of　(Ca,Ti)2(Nb,Ti)2O7/yttria-stabilized　zirconia,　the　films　directly　grow　on　the　substrates.　In　contrast,　in　the　(Ca,Ti)2(Nb,Ti)2O7/LaAlO3　heterosystem,　a　perovskite-type　Ca1-(Ti,Nb)O3　interlayer　with　a　few　unit　cells　in　thickness　forms　at　the　interface　and　interfacial　reconstruction　occurs　at　the　(Ca,Ti)2(Nb,Ti)2O7/Ca1-(Ti,Nb)O3　interface.　Our　findings　indicate　that　the　formation　of　the　interlayer　and　the　(Ca,Ti)2(Nb,Ti)2O7/Ca1-(Ti,Nb)O3　interface　reconstruction　can　accommodate　the　film/substrate　dissimilarities　in　the　crystal　structures　and　facilitate　the　growth　of　single-crystalline　pyrochlore-type　films　on　the　perovskite-type　substrates.　©　2021