<p>Herein, MOF-303@PVA electrospun fibers that employ water-synthesized MOF-303 as the filler and environmentally water-soluble polyvinyl alcohol (PVA) as the matrix via electrospinning followed by vapor-phase crosslinking were developed and proposed as adsorbents for Cu²⁺ removal from aqueous solutions. MOF-303 can be firmly immobilized within a three-dimensional, high-surface-area PVA network through hydrogen-bonding interactions. This approach ensured the preservation of the MOF structure and adsorption sites while promoting the transport and diffusion of ions, ultimately leading to a high adsorption capacity of Cu²⁺. The electrospun fibers were characterized by XRD, FTIR, SEM, BET, and TGA. The effects of key parameters including Cu²⁺ concentration, contact time, adsorbent dosage, and pH on adsorption performance were systematically investigated. The maximum adsorption capacity of MOF-303@PVA electrospun fibers for Cu²⁺ can reach 114.27&#xa0;mg/g, and the adsorption mechanism conforms to the Freundlich model and pseudo-second-order kinetic model. In addition, the MOF-303@PVA electrospun fibers can be regenerated and reused for multiple cycles while maintaining high adsorption recovery rate (3cycles, &gt; 88%), and the adsorption performance of MOF-303@PVA electrospun fibers can still retain of 97% after being immersed in water for 14&#xa0;days, indicating that MOF-303 loaded in the three-dimensional network electrospun fibers has a low dissolution rate.</p>