This study uses the MHD (Magnetohydrodynamics) model to simulate unsteady two-dimensional transport variables in helium plasma under low pressure between two infinite planar electrodes suddenly biased by a negative voltage. Plasma has been widely used in etching, ion implantation, light source, and encountered in nuclear fusion, etc. Studying transport processes of plasmas therefore is important. By account for momentum exchange collisions, electric fields and magnetic fields the computed results in this work quantitatively show density, velocity, electric potential, temperature, viscosity, thermal conductivity of the ions and electrons across the sheath to the surfaces suddenly biased by a dc negative voltage.