The　ceramic　samples　of　BaTiO3+1/2xLn(2)O(3)+2mol%TiO2　(0.001　＜=　x　＜=　0.01)　were　prepared,　where　Ln　is　Y,　Dy,　Ho,　Er　or　Y.　The　influence　of　rare　earth　on　the　resistivity　and　microstructure　of　the　samples　was　investigated　by　the　means　of　XRD,　SEM　and　electric　properties　testing.　The　results　showed　that　the　resistivity　of　La-doped　sample　decreases　when　x=　0.003　compared　with　the　undoped　sample.　However,　the　range　of　dopant　concentration　with　Dy,　He,　Er　or　Y　for　semiconducting　samples　is　wider,　especially　for　Y-doping.　Minimum　resistivity　at　room　temperature　was　observed　when　x=0.003,　which　is　named　after　the　critical　concentration.　The　experimental　results　indicated　that　below　the　critical　concentration　of　Dy,　Ho,　Er　or　Y,　the　substitution　took　place　in　the　barium　sublattice　with　electronic　compensation,　and　the　rare　earth　ions　began　to　substitute　for　titanium　gradually　above　the　critical　concentration.　For　Ho-doped　BaTiO3　ceramic,　the　resistivity　jump　(PTCR　effect)　near　the　Curie　temperature　was　the　highest　in　the　case　of　x=0.003.　Fine-grained　structure　of　the　sample　doped　with　0.6mol%　Dy　led　to　the　increase　of　breakdown　field　strength　and　dielectric　constant　of　ceramic　samples.