<p>Constructing functional polymer layers on zinc (Zn) anodes enhances the stability of Zn anodes. However, conventional polymer coatings cannot effectively coordinate Zn²⁺ deposition with water-induced side reactions due to their single and limited chemical composition. Here, through C–H functionalization technology, maleic anhydride (MA) is grafted onto tetra-arm polyethylene glycol (4-arm PEG). Subsequently, a crosslinked porous polyether protective layer (CFPG) is formed <i>in situ</i> on Zn anodes through esterification/amidation reactions, where amino-β-cyclodextrin (NH₂-β-CD) is employed as the crosslinking agent. The cavities of NH₂-β-CD can adsorb Zn²⁺ via supramolecular interactions, forming nanochannels for Zn²⁺ transport, while the 4-arm PEG and NH₂-β-CD peripheries form a continuous hydrogen-bonded receptor network confining water molecules. Therefore, CFPG effectively suppresses side-reactions and ensures long-term battery performance. The CFPG@Zn symmetric cell achieves stable cycling for 3000 h at 1 mA cm⁻², 2200 h at 5 mA cm⁻², and over 1100 h at a high discharge depth of 40%. The full-cell with VO₂ cathode delivers 3000 cycles at high mass-loading of 7.9 mg cm⁻². It also maintains 1000 cycles under stringent conditions (12.3 mg cm⁻², 40-µm Zn). This study presents a crosslinked porous polymer network with ion-selective channels as a novel approach to advanced interfacial layer design.</p>