The characteristic mode (CM) theory has been widely recognized as a powerful tool for radiation/scattering analysis and optimization designs. As a natural extension of PEC CM theory and dielectric material CM theory, we propose a novel CM formulation for the systematic analysis of dielectric coated conducting bodies. The newly developed CM formulation bases on the EFIE-PMCHWT equation. Numerical cases show the validity and accuracy of the proposed CM formulation in calculating characteristic currents and characteristic fields and predicting resonant frequencies.