The　synergistic　effects　of　double　doping　with　a　positive　mismatch　perovskite　(Ba2YNbO6)　and　a　negative　mismatch　perovskite　(LaAlO3)　on　the　brittle　ceramic　YBa2Cu3O7-x　(YBCO)　superconducting　films　were　investigated.　The　double-doped　sample　allows　a　greater　doping　amount　than　any　single　doping,　with　significantly　smaller　nanostrain　on　the　c　axis,　and　shows　superior　superconducting　properties.　By　analyzing　the　crystal　mismatch　and　establishing　a　suitable　model　of　the　doping　effects,　it　was　found　that　the　double　doping　with　the　positive　mismatch　and　the　negative　mismatch　dopant　cancels　the　long-range　strain　but　still　generates　defects　around　the　interface　between　the　YBCO　and　the　dopants,　simultaneously.　This　result　reveals　a　feasible　method　for　solving　the　problem　of　degradation　and　even　cracks　in　the　YBCO　film　due　to　the　excess　doping　amount.　This　approach　provides　a　wider　compositional　space　for　the　design　and　fabrication　of　more　ingenious　pinning　structures　in　the　YBCO　film　for　meeting　the　criteria　of　specific　applications.