Zn　metal　has　been　regarded　as　one　of　the　most　promising　metal　anodes　for　aqueous　batteries,　but　it　still　suffers　from　undesirable　dendrites　growth　and　serious　side-reaction　during　cycling.　So　far,　various　additives　have　been　developed　to　achieve　uniform　deposition　of　zinc,　but　they　have　failed　to　fundamentally　overcome　intrinsic　fragile　morphology　of　the　deposited　metallic　zinc.　Herein,　the　polyaspartic　acid　(PASP)　was　introduced　into　aqueous　electrolyte　to　cope　with　the　problems　in　two　aspects.　One　is　to　modulate　the　morphology　of　deposited　metallic　Zn　from　large,　fragile　and　loosely　piled　platelets　to　small　and　homogeneous　spherical　particles,　to　achieve　dendrite-free　Zn　deposition　by　PASP　additive.　On　the　other　hand,　the　ability　to　resist　the　side-reaction　on　Zn　anode　can　be　significantly　improved　via　PASP　additive.　Both　ensure　the　cyclic　stability　and　high　Coulombic　efficiency　(CE)　during　the　reversible　Zn　plating　and　stripping.　With　the　addition　of　PASP,　Zn　||　Zn　symmetrical　cells　can　stably　cycle　over　3200　h　at　0.5　mA　cm−2　and　2000　cycles　at　20　mA　cm−2,　while　Zn　||　V2O5　full　cells　can　maintain　a　CE　of　nearly　100%　for　2500　cycles　at　10　A　g−1.　We　believe　that　the　use　of　PASP　as　electrolyte　additive　is　a　feasible　approach　for　practical　applications　of　the　aqueous　rechargeable　zinc　batteries　in　the　future.　©　2021