This　work　proposed　pyrochlore　doped-Pr2Sn2O7　ceramics　with　electronic　transport　and　NO2　sensitivity　through　molecular　insights　into　sensing　mechanism　by　DFT.　NO2　adsorbed　on　the　p-type　semiconductor　metal　oxide　NiO　(100)　can　be　decomposed　into　three　stable　adsorbed　states　NO2,　NO　and　O　that　will　obtain　electrons　from　the　NiO　valence　band　to　form　N-2　(or　N2O)　and　O2-,　resulting　in　an　increase　of　the　holes　concentration.　The　results　suggest　that　the　response　current　value　of　the　sensor　based　on　Pr2Sn2O7　doped　by　Ca2+　at　A　site　is　53.5　times　higher　than　that　of　commercial　YSZ,　indicating　high　sensitivity　with　420　nA/ppm　at　mild　temperature　550　degrees　C.　Besides　the　creation　of　oxygen-defect　sites,　the　electronic　transport　is　responsible　for　the　improved　sensing　properties.　The　electrons　on　doped　Pr2Sn2O7　ceramics　can　complement　the　hole-accumulation　layer　and　make　NO2,　NO,　O　accept　electrons　quickly　to　accelerate　the　rate　of　the　electrochemical　cyclic　reaction.