Lithium metal anode is regarded as promising potential electrode for next-generation secondary batteries. However, the security issues caused by the growth of lithium dendrites hinder the development of lithium metal batteries. In this study, we prepare a single-ion conducting polymer electrolyte with semi-interpenetrating polymer network based on poly(lithium 4-styrenesulfonate). By eliminating the large electric fifields near the lithium anode, the growth of lithium dendrite is suppressed effffectively according to space-charge theory. The structurally optimized poly(lithium 4-styrenesulfonate)@polymethylmethacrylate single-ion conducting polymer electrolyte containing 2 wt% ethylene glycol dimethacrylate exhibits extremely high lithium ion transference number (0.91), promising ionic conductivity (0.97 × 10?3 S cm?1 at 25 °C) along with wide electrochemical window of 4.7 V (vs. Li+/Li). Furthermore, the LiFePO4/membrane/Li cell achieves stable cycling performance (capability retention rate of 93.8% after 78 cycles at 1 C (1 C = 170 mAh g?1) and high coulombic effiffifficiency 99.4%) along with superior discharge rate capability at room temperature. These excellent performances show that the single-ion conducting polymer electrolyte is a potential candidate for safe lithium metal batteries.