Vanadium-based alloys possess high hydrogen storage capacities but suffer from severe cyclic decay. Herein, we demonstrate that the electronegativity difference between V and alloying elements (ΔχV-M) fundamentally governs local hydrogen distribution, thereby dictating phase evolution and cyclic stability. Specifically, alloying with Fe (ΔχV-M = −0.20) intrinsically weakens local H–metal interactions, giving rise to H-depleted regions. The resulting heterogeneous hydrogen distribution suppresses irreversible interstitial H trapping and spatially confines the phase transformation. Consequently, localized atomic rearrangement is effectively restricted, mitigating lattice mismatch and significantly reducing continuous capacity degradation. In contrast, alloying with Zr (ΔχV-M = +0.30), strengthens H–metal interactions, promotes local hydrogen enrichment, expands the phase transformation region, and accelerates cycling degradation. These findings reveal the pivotal role of electronegativity in regulating degradation behavior from an electronic-structure perspective and establish ΔχV-M as a practical design descriptor for developing highly cycle-stable hydrogen storage alloys.