Superconducting　cosmic　strings　(SCSs)　have　received　revived　interests　recently.　In　this　paper　we　treat　closed　SCSs　as　oriented　knotted　line　defects,　and　concentrate　on　their　topology　by　studying　the　Hopf　topological　invariant.　This　invariant　is　an　Abelian　Chern-Simons　action,　from　which　the　HOMFLYPT　knot　polynomial　can　be　constructed.　It　is　shown　that　the　two　independent　parameters　of　the　polynomial　correspond　to　the　writhe　and　twist　contributions,　separately.　This　new　method　is　topologically　stronger　than　the　traditional　(self-)linking　number　method,　which　fails　to　detect　essential　topology　of　knots　sometimes,　shedding　new　light　upon　the　study　of　physical　intercommunications　of　superconducting　cosmic　strings　as　a　complex　system.