Quantum　private　comparison　(QPC)　protocol　can　guarantee　the　two　participants　to　compare　the　equality　of　their　private　information　without　leaking　them.　Based　on　the　entanglement　swapping　between　the　four-qubit　cluster　state　and　extended　Bell　state,　an　efficient　QPC　protocol　has　been　proposed.　Three　bits　of　the　secret　inputs　have　been　compared　in　each　comparison　time,　which　improves　the　efficiency　compared　with　the　previous　QPC　protocols＇　one　or　two　bits.　Then,　based　on　a　random　sequence　pre-shared　between　the　two　participants,　the　semi-honest　third　party　can　only　execute　the　protocol＇s　process　without　obtaining　the　information　of　the　participants＇　secrets　and　comparison　results.　Last,　various　kinds　of　attacks　have　been　analyzed,　which　show　that　the　proposed　protocol　is　secure　against　the　outside　and　participants　attacks.