In　this　paper,　the　extended　finite-element　method　(XFEM)　is　employed　to　analyze　electric　field　of　insulating　plate　with　crack.　To　begin　with,　both　the　approximation　of　XFEM　and　features　of　the　enrichment　functions　for　crack　tip　are　presented.　Then,　XFEM　is　used　to　solve　electric　potential　of　an　insulating　plate　with　a　middle　crack,　which　proves　the　method　can　save　computational　time　by　comparison　with　classic　finite-element　method　(CFEM)　under　the　same　computational　accuracy.　In　addition,　XFEM　is　also　applied　to　calculate　electrical　field　at　crack　tip　of　an　insulating　plate　with　an　edge　crack,　which　reveals　that　the　relative　error　between　XFEM　and　CFEM　is　small　when　the　meshing　size　of　CFEM　around　crack　tip　is　smaller　than　that　of　XFEM.　Therefore,　electric　field　analysis　of　discontinuous　and　singular　solutions　can　demonstrate　the　superior　performance　of　XFEM.