Generally,　the　basic　parameters　of　conventional　cathodic　protection　design　mostly　rely　on　theoretical　or　empirical　approximate　formulas.　An　over　protection　phenomenon　has　emerged　for　pipeline　systems　with　large　scale　differences　in　soil　environment.　This　paper　investigated　the　basic　parameters　of　the　electric　cathodic　protection　under　three　types　of　simulated　soil　solution　environments　(Korla　station,　Lhasa　station　and　Yingtan　station)　for　X100　high　strength　pipeline　steel　by　using　the　technology　of　electrochemical　impedance　spectroscopy　(EIS)　combined　with　polarization　curves.　The　results　showed　that　the　EIS　and　polarization　curves　can　help　determine　the　basic　parameters　for　X100　high　strength　pipeline　steel　cathodic　protection　under　the　above　three　simulated　soil　solution　environments.　Also,　the　changing　characteristics　of　charge　transfer　resistance　(R-t)　and　cathode　potential　change　(E)　changes,　can　be　achieved　by　fitting　EIS　results:　with　negative　potential　shifting,　R-t　appeared　a　maxima　value;　Hydrogen　evolution　reaction　started　at　the　stage　when　R-t　＜1000　Omega.cm(2)　;　For　X100　high　strength　pipeline　steel　under　different　simulated　soil　solution　environments　at　Korla　station,　Lhasa　station　and　Yingtan　station,　the　size　of　hydrogen　evolution　potential　was　successively　reduced.