Response　of　PIN　diode　is　numerically　simulated　by　a　self-developed　2D　semiconductor　device　simulation　GSRES　to　study　the　response　behavior　of　PIN　diode　limiter　under　electromagnetic　pulse　(EMP).　Current　overshoot　phenomena　of　PIN　diode　during　the　rise　time　of　EMP,　which　is　validated　to　be　due　to　the　capacitive　performance　of　PIN　diode　under　high　frequency,　are　analyzed.　Shorter　rise　time　of　EMP　causes　higher　current　peak　value.　Overshoot　current　is　affected　by　the　impurity　doping　concentration　of　PIN　diode.　Higher　doping　concentration　of　impurity　in　the　P　layer　and　N　layer　causes　higher　peak　of　current　and　sooner　attenuation　of　overshoot　current.　Doping　concentration　of　the　I　layer　affects　the　overshoot　current　too,　but　not　as　salient　as　concentration　of　the　P　and　N　layers.　These　results　can　be　used　in　radiation　hardening　for　PIN　diode　limiter.