The change of plasma parameter spatial profile was stutied on $O_2$ electron cyclotron resonance plasma. At the transition point of density and ion saturation current, the spatial profile of electron density, ion saturation current and emission intensity is also changed. At 1.6 mTorr, the first transition is occured near 420 Watt and the shape of spatial ion saturation current profile is changed from flat to high centered. As encreasing pressure, the power where the transition apprear is decreased but the ion saturation current at this point is nearly same. This implies an mode transition which is caused by transformation of polarization from transverse wave to longitudinal one. As a reason of high centered $I_is$ profile, transition power difference for radial position is suggested. Second transition is obsereved near 540 Watt. $I_is$ is slowly increasing from this point, and spatial profile is changed from high centered to hollow one.