Understanding　the　function　of　individual　elements　in　high　-entropy　perovskites　is　one　of　the　critical　issues　for　the　design　of　inexpensive　and　efficient　bifunctional　electrocatalysts.　Here,　we　report　our　findings　in　boosting　the　electrochemical　activity　and　durability　of　a　high　-entropy　perovskite　catalyst　via　sequential　substitution　of　Sr2+　for　the　A　-site　elements.　According　to　the　Sr2+　localized　tuned,　the　catalyst　of　(LaSmGdSrPr)0.2MnO3　has　a　halfwave　potential　of　0.786　V　vs.　RHE　and　an　overpotential　of　0.378　V　and　has　better　ORR　and　OER　electrocatalytic　activity　than　the　Sr　-free　high　-entropy　perovskite　catalyst　(LaSmGdYPr)0.2MnO3.This　is　attributed　to　the　local　doping　of　Sr2+　activating　the　active　center　of　the　high　-entropy　perovskite　catalyst　(LaSmGdSrPr)0.2MnO3,　modulating　the　adsorption　energy　of　the　oxygen　-containing　intermediates　and　the　electronic　structure　of　the　transition　metal　at　the　B　-site,　which　results　in　efficient　oxygen　electrocatalytic　activity.　On　the　other　hand,　the　introduction　of　Sr2+　enhances　the　hybridization　between　Mn　2p　and　O　1　s　and　accelerates　the　adsorption　and　desorption　kinetics　of　the　intermediates,　leading　to　both　enhanced　activity　and　durability　of　(LaSmGdSrPr)0.2MnO3.　DFT　theoretical　calculations　also　demonstrate　the　key　role　played　by　Sr2+　in　the　highentropy　perovskite　structure　for　the　improvement　of　the　electrocatalytic　activity.　This　study　provides　new　insights　for　designing　high　-entropy　electrocatalysts　for　various　potential　applications.