Abstract: On November 23, 1982, an extremely high-speed stream was overtaking a strong magnetic field structure, resulting in an interplanetary combinative structire including high-density front sheath, main part with strong magnetic field and low density, high density rear sheath, and extremely high-speed streams. The MHD characteristics of the combinative structure are analyzed in this paper. A sub-Alfvenic flow is found inside the main part of the strong magnetic field structure, the formation of which is also discussed.