A conventional magnetron and a coaxial electrosolenoid were used to construct an unbalanced magnetron sputtering deposition system for investigating its properties. At 02Pa, argon gas discharging, a shielded planar ioncollecting electrode was taken to measure the saturation ion beam flux density at the different axial positions. The saturation ion flux reached about 9mA/cm2. The magnetohydrodynamics was applied to analyse the influences of the magnetic mirror effect on the discharge properties caused by the solenoid. As a result, the comparisons of the theoretical calculations with the experiments indicated that the model described correctly the plasma properties in the unbalanced magnetron sputtering system.