Tuning　the　d-orbital　electronic　configuration　of　active　sites　to　achieve　well-optimized　adsorption　strength　of　oxygen-containing　intermediates　toward　reversible　oxygen　electrocatalysis　is　desirable　for　efficient　rechargeable　Zn-Air　batteries　but　extremely　challenging.　Herein,　this　work　proposes　to　construct　a　Co@Co3O4　core-shell　structure　to　regulate　the　d-orbital　electronic　configuration　of　Co3O4　for　the　enhanced　bifunctional　oxygen　electrocatalysis.　Theoretical　calculations　first　evidence　that　electron　donation　from　Co　core　to　Co3O4　shell　could　downshift　the　d-band　center　and　simultaneously　weak　spin　state　of　Co3O4,　result　in　the　well-optimized　adsorption　strength　of　oxygen-containing　intermediates　on　Co3O4,　thus　contributing　a　favor　way　for　oxygen　reduction/evolution　reaction　(ORR/OER)　bifunctional　catalysis.　As　a　proof-of-concept,　the　Co@Co3O4　embedded　in　Co,　N　co-doped　porous　carbon　derived　from　thickness　controlled　2D　metal-organic-framework　is　designed　to　realize　the　structure　of　computational　prediction　and　further　improve　the　performance.　The　optimized　15Co@Co3O4/PNC　catalyst　exhibits　the　superior　bifunctional　oxygen　electrocatalytic　activity　with　a　small　potential　gap　of　0.69　V　and　a　peak　power　density　of　158.5　mW　cm(-2)　in　ZABs.　Moreover,　DFT　calculations　shows　that　the　more　oxygen　vacancies　on　Co3O4　contribute　too　strong　adsorption　of　oxygen　intermediates　which　limit　the　bifunctional　electrocatalysis,　while　electron　donation　in　the　core-shell　structure　can　alleviate　the　negative　effect　and　maintain　superior　bifunctional　overpotential.