Composite solid electrolytes (CSEs) consisting of polymers and fast ionic conductors are considered a promising strategy for realizing safe rechargeable batteries with high energy density. However, randomly distributed fast ionic conductor fillers in the polymer matrix result in tortuous and discontinuous ion channels, which severely constrains the ion transport capacity and restricts its practical application. Here, CSEs with highly loaded vertical ion transport channels are fabricated by magnetically manipulating the alignment of Li_0.35La_0.55TiO₃ nanowires. The construction of densely packed, vertically aligned ion transport channels can effectively enhance the ion transport capacity of the electrolyte, thereby significantly increasing ionic conductivity. At room temperature (RT), the presented CSE exhibits a remarkable ionic conductivity of up to 2.5 × 10⁻⁴ S cm⁻¹. The assembled LiFePO₄/Li cell delivers high capacities of 118 mAh g⁻¹ at 5 C at 60 °C and a RT capacity of 115 mAh g⁻¹ can be achieved at a charging rate of 0.5 C. This work paves an encouraging avenue for further development of advanced CSEs that favor lithium metal batteries with high energy density and electrochemical performance.