Using cheap sodium silicate as a silica source and surfactant P123 as a soft template, an environment-friendly mesoporous material, COK-12, was prepared in a near-neutral environment. COK-12 was modified with n-hexane to obtain an H-COK-12 template with a compact and ordered pore structure. In this study, the modified mesoporous material H-COK-12 was used as the template for the first time, and the mesoporous La0.8Sr0.2CoO3 (LSC) catalyst was prepared by nano-casting method combined with sol–gel method. The results showed that the LSC-650 catalyst synthesized at 650 °C for 2 h possessed a large specific surface area (103.46 m2/g) and the highest surface Co4+/Co3+ and Oads/Olat molar ratio. In addition, the CO conversion with the LSC-T (T = 550, 600, 650, 700 °C) samples indicated that the LSC-650 sample had the best catalytic activity (T50 = 145 °C, T90 = 149 °C) and stability.