The morphology of PE in the in-situ CB/PE composites prepared from in-situ polymerization via a catalystsupported approach was studied by DSC. It is found that both the melting peak temperature and crystallinity of the PE shell decrease as filler level increases. The unexpected phenomena are ascribed to the strong interaction between PE and CB and the very high specific area of CB. It is suggested that the lamellar thickness should be well correlated to the PE shell thickness. A two-layer PE model is successfully used to explain the experiment results.