Silica network-encapsulated cobalt nanoparticles with an adjustable pore structure as model Fischer-Tropsch synthesis catalysts were successfully prepared. The well-developed shell pore structure of the core-shell catalyst is of great importance for reducing the selectivity of methane, increasing the selectivity of heavy hydrocarbons, and the probability of carbon chain growth. Benefiting from its uniform distribution of cobalt particles and 3D open hierarchical porous shell features, Co@H-mSiO2 catalysts exhibited excellent stability and activity, achieving up to 61.4% selectivity of C5-C20 hydrocarbon products at 6 SL h-1 g-1, 220 °C and 1.0 MPa.