The crystallization behavior of n-C19H40/SiO2 nanosphere composites was investigated by a combination of differential scanning calorimetry (DSC) and temperature-dependent X-ray diffraction (XRD). Three kinds of confined alkalies with different Solid-solid phase transition supercoolings and a surface (or interface) freezing monolayer of n-C19H40 at the bulk liquid/SiO2 interface were Found in the composites at high SiO2 loading. The Surface freezing monolayer induces the chain packing or bulk alkalies by forming a 2D close-packed arrangement Without long-range positional ordering in 3D space. A homogeneous nucleation and growth mechanism is found for the solid-solid transition in confined geometry, in which the supercooling of the transition is sensitive to the confined size.