Abstract: The nano-phase microstructure of high molecular weight poly(ε-caprolactone) (PCL) /silica hybrid materials, in which polymeric and inorganic component are coupled by hydrogen bonding, and nucleation and growth of PCL chain in the hybrids were studied by scanning electronic microscopy, wide-angle X-ray diffraction and differential scanning calorimetry. The results show that the micro-phase separation in the hybrids occurs at the nano-meter scale. The average scale of the polymeric domain is about 70 nm. The morphological structure of the inorganic component appears as irregular particles. The uniform distribution of two phases relates to the bonding strength of hydrogen bonding between components in the hybrids. After a PCL is hybridized, the relative degree of crystallinity decreases and the corresponding scale of microlite change. In addition, with inorganic content increasing, the equilibrium melting points of the PCL in hybrids decrease. The energy that polymeric chains fold to form crystals on the surface of crystal nucleus increases. This result is due to the influence of silica and the bonding strength in hybrids.