In the surface treatment by plasma, the saturation ion current is the macroscopic parameter which can give us information on the ionic density in plasma. For this, we followed the evolution of the saturation ion current versus the pressure and power. Our experimental setup consists of spherical plasma reactor linked with inductively source argon plasma and probe to measure ionic current. The obtained experimental results enabled us to highlight the effect of pressure and power on saturation ion current. We found in this study that the saturation ion current increases with pressure and presents an optimum depending on the power.