Distribution　of　conductors　in　a　substation　is　complex,　usually　the　span　and　sag　of　two　sets　of　jointed　conductors　are　different.　Traditional　charge　simulation　method　(CSM)　calculate　the　electric　field　using　lumped　parameter,　with　the　hypothesis　that　the　span　and　sag　of　two　sets　of　conductors　jointed　together　are　equal,　which　lead　to　the　electric　field　obtained　where　conductors　are　joint　to　be　discontinuous.　The　paper　proposes　an　electric　field　model,　the　model　improves　CSM　using　distributed　parameter,　it　calculate　electric　field　according　to　the　difference　of　span　and　sag　of　two　sets　of　conductors　which　are　jointed　together.　it　can　calculate　the　electric　field　in　a　substation　more　accurately,　and　continuous,　smooth　electric　field　is　obtained.　The　method　can　be　applied　to　calculating　electric　fields　under　various　conductor　arrangements.　Advantages　of　the　method　arc　proved　by　simulation　in　Matlab.