Severe lithium (Li) dendrite growth caused by the uneven overpotential deposition is a formidable challenge for high energy density Li metal batteries (LMBs). Herein, we investigate a synergetic interfacial kinetic to regulate Li deposition behavior and stabilize Li metal anode. Through constructing Li alloying matrix with a bi-functional silver (Ag)-Li₃N blended interface, fast Li⁺ conductivity and high Li affinity can be achieved simultaneously, resulting in both decreased Li nucleation and mass transfer-controlled overpotentials. Beyond these properties, a more important feature is demonstrated herein; that is, the inward diffusion depth of the Li adatoms inside of the Ag site can be restricted by the Li⁺ solvation structure in a highly coordinating environment. The latter feature can ensure the durability of the operational Ag sites, thereby elongating the Li protection ability of the Ag-Li₃N interface greatly. This work provides a deep insight into the synergetic effect of functional alloying structure and Li⁺ solvation mediated interfacial kinetic on Li metal protection.