Poly(styrene-b-caprolactone)/silicate nanocomposites were prepared via one-pot, one-step in-situ living polymerization from a silicate-anchored bifunctional initiator. The random dispersion of the silicate layers in the polymer matrix was confirmed by both XRD and STEM. The polymer chains were attached to the surface of the silicate layers at the junction between the two blocks. SEC and NMR confirmed the block structure of the polymer. Through simultaneous incorporation of the initiator and benzyltrimethylammonium salt as a noninitiator into the silicate nanocomposites containing higher molecular weight polymers were obtained. The molecular weights of the polymers and the silicate content of the nanocomposites were also controlled. Characterization by XRD and DSC showed that the poly(caprolactone) segment existed in a crystalline state.