AbstractMetal–organic frameworks (MOFs) with accurately directional and well‐ordered channels are considered ideal solid‐state Li‐ion conductors and are expected to be utilized in solid‐state lithium–oxygen (Li–O₂) batteries to achieve rechargeable batteries with high energy density. However, the instability of MOFs toward air and lithium metal has become a crucial problem to overcome. Herein, a breakthrough is first realized in overcoming these challenges by utilizing cationic MOF (CMOF) as an advanced Li‐ion conductor. Benefiting from the positively charged sites in the CMOF, an outstanding Li⁺ conductivity of 6.45 × 10⁻⁴ S cm⁻¹ at room temperature, a low activation energy of 0.15 eV, and a high transference number of 0.59 are achieved. In particular, the CMOF shows high flame retardancy, H₂O, and O₂⁻ stability, which are key factors that affect the battery performance of Li–O₂ batteries. Such extraordinary Li⁺ transport makes the assembled solid‐state Li–O₂ battery cycle up to 790 h with a low overpotential of 1.09 V. The proposed novel directional modification strategy is of great significance to developing high‐performance SSEs for solid‐state Li–O₂ batteries and other lithium batteries.