Flexible Zn‐ion batteries (ZIBs) emerge as a promising entrant for flexible and safe energy systems in the post‐Li era, while the instability of Zn anode including inferior flexibility, uncontrollable plating, and dendrite growth remains a challenge. Naturally inspired, a topology‐optimized biomimetic honeycomb Zn (BH‐Zn) anode through mechanical‐electrochemical processing is demonstrated. Numerical simulations and experimental observations reveal the BH‐Zn engenders smooth current–stress–thermal field distributions, concurrently realizing the multi‐field regulation effect and boosted stability. After in situ alloying, the BH‐Zn enables half‐diminished voltage polarization, superior electrochemical stability of 2000 h cycling, and thermal stability even at 30 mA cm−2. Moreover, the assembled ZIBs manifest over 20 times enhanced capacity retention and are integrated as a self‐powered wearable system for real‐time health monitoring. This strategy can be extended to customizable metal anodes and promises to be applied in stable flexible batteries. [ABSTRACT FROM AUTHOR]