Abstract: Based on the two-dimensional magnetohydrodynamic(MHD) theory, the magnetic field penetration process at the conduction stage of a high-density, coaxial plasma opening switch (POS) was numerically simulated, and the evolution of the magnetic field distribution with time was obtained. The influence of the energy transportation on the magnetic field penetration was studied. It is shown that the magnetic field penetrates into the plasmas rapidly, and the temperature in the shock region increases greatly. The non-uniform distribution of temperature resulted from the compression of the plasma and the Ohmic heating speeds up the magnetic field penetration significantly. The conduction-time of the POS is 0.87 μs by the model with the energy transportation, which is shorter than that of the isothe