Abstract: To address the bottlenecks of insufficient water retention, low actuation output efficiency, and significant back-relaxation effects faced by ionic polymer-metal composites (IPMCs) in practical applications, a synergistic optimization strategy of "internal moisture retention-electrode regulation" is proposed. First, hydrogen bond networks were constructed by doping ethylene glycol (EG) into the Nafion base membrane to significantly enhance the intrinsic water retention capability of the material. Second, an isopropanol (IPA)-assisted electroless plating process was employed, utilizing its steric hindrance effect to induce uniform and dense deposition of the silver electrode. The results indicated that when the volume ratio of Nafion to EG was 4∶1, the initial water content of the IPMC reached 73.61±1.21%(n=3), which was 2.60 times that of the conventional sample, and water retention stability was significantly enhanced. For the 3I-IPMC sample prepared via IPA assistance, the tip displacement and actuation rate were increased to 2.94 and 2.68 times those of the conventional sample, respectively, while the back-relaxation rate was reduced to one-third of the original. Microstructural analysis revealed that the branched structure of IPA effectively inhibited the disordered diffusion of silver ions, forming a highly dense electrode; this increased the elastic modulus of the material to 504 MPa and improved comprehensive mechanical properties. Dynamic response tests further verified that the optimized IPMC possessed the excellent characteristics of "fast actuation-low relaxation". This study achieves a multidimensional synergistic improvement in the water content, actuation performance, and stability of IPMCs through the organic combination of material modification and process innovation. It provides new insights for their practical application in fields such as soft robotics and precision medical devices.