Metallic Zn is a promising anode for high-safety, low-cost, and large-scale energy storage systems. However, it is strongly hindered by unstable electrode/electrolyte interface issues, including zinc dendrite, corrosion, passivation, and hydrogen evolution reactions. In this work, an in situ interface protection strategy is established by turning the corrosion/passivation byproducts (zinc hydroxide sulfates, ZHSs) into a stable hybrid protection layer. The hydrolysis of the diglycolamine buffer layer on the zinc anode provides a homogeneous basic electrolyte environment for the generation of small-sized ZHS, thereby leading to the formation of a ZHS-based hybrid layer. Benefiting from this hybrid layer, uniform zinc ion flux and high anticorrosion ability can be achieved. As a result, the decorated symmetric cell presents a long cycling lifespan of over 1500 h at a current density of 1 mA cm-2 and an area capacity of 1 mAh cm-2. It also contributes to the appealing cycling and rate performance of Zn|NH4V4O10 full cells. This work provides insight into regulating and reusing interfacial byproducts for high-performance zinc metal batteries.