Crystallization and phase transition behaviors of n-hexadecane (n-C16H34, abbreviated as C-16) confined in microcapsules and n-alkane/SiO2 nanosphere composites have been investigated by the combination of differential scanning calorimetry (DSC) and temperature-dependent X-ray diffraction (XRD). As evident from the DSC measurement, the surface freezing phenomenon of C-16 is enhanced in both the microcapsules and SiO2 nanosphere composites because the surface-to-volume ratio is dramatically enlarged in both kinds of confinement. It is revealed from the XRD results that the novel solid solid phase transition is observed only in the rnicroencapsulated C-16, which crystallizes into a stable triclinic phase via a mestastable rotator phase (RI). For the C-16/SiO2 composite, however, no novel rotator phase emerges during the cooling process, and C-16 crystallizes into a stable triclinic phase directly from the liquid state. Heterogeneous nudeation induced by the surface freezing phase is dominant in the microencapsulated sample and contributes to the emergence of the novel rotator phase, whereas heterogeneous nucleation induced by foreign crystallization nuclei dominates the C-16/SiO2 composite, leading to phase transition behaviors similar to those of bulk C-16.