Nano-Ag　sintering　can　realize　superior　thermal,　electrical,　and　mechanical　properties　for　power　electronic　packaging,　while　it　suffers　from　unstable　microstructure　and　electrochemical　migration.　In　this　work,　a　super-saturated　Ag2.8　wt%Cu　nanoalloy　film　has　been　developed　using　pulsed　laser　deposition,　which　can　be　sintered　at　250　degrees　C　in　air　for　electronic　packaging　without　sacrificing　bondability.　It　was　surprisingly　found　that　both　thermal　stability　and　electrochemical　migration　resistance　were　significantly　improved　when　alloying　the　Ag　with　2.8　wt%　Cu.　The　in　situ　formed　Cu2O/CuO　from　Ag-Cu　nanoalloy　existed　on　the　pore　surface　and　along　the　grain　boundaries　of　Ag/Ag-Cu　nanoalloy,　which　stabilized　the　microstructure　of　bondline　from　400　h　to　1400　h　at　300　degrees　C.　The　synergistic　effect　of　Ag-Cu　nanoalloy　and　Cu　oxides　realized　an　obvious　protective　effect　in　the　process　of　anodic　dissolution,　exhibiting　a　short-circuit　time　2.4　times　of　the　pure　Ag　electrode.　The　die　attach　process　is　compatible　with　most　commercial　equipment　and　Si/SiC　dies　with　improved　performance,　enabling　the　supersaturated　Ag-Cu　nanoalloy　to　be　a　promising　material　for　high　reliability　power　electronic　packaging.