Tounderstandthemooringenergyduringpositioning,theexpressionsoffouritemsconcerningmooringlineenergyarepresentedbasedonafiniteelementmodel,includinggravitationalandelasticpotentialenergy,kineticenergyanddissipatedenergyduetomooring-induceddamping.Inastaticcase,theforcecalculatedfromthederivativeofpotentialenergywithrespecttodistanceiscomparedwiththatofdirectcalculation.Theresultsarefoundfitwell,whichindicatesthelawofconservationofenergyandalsoshowsthecorrectnessofthepotentialenergyresults.Forthecasesofasinglemooringlinewiththeattachmentpointoscillatingwithdifferentamplitudesinhorizontalorverticaldirection(correspondingtosurgeandrollmotionsrespectively),andthecaseofthemooringlinewithahorizontalbichromaticoscillationontheattachmentpoint,thetimehistoryofthefirstthreeitemsarecalculatedandanalyzed,also,theindicatordiagramformooring-induceddampingaregiven.Theseresultsrevealtheenergystateofthemooringlineandcanprovideabetterunderstandingofhowthemooringlineworks.