The RF O-2-plasma treatments show significant changes in the nature and relative ratio of Surface atoms in kraft lignin compounds. The comparisons between the treatments and the measured results reveal that the oxidation response of a kraft lignin can be predicted quite well by changing the external plasma parameters. The XPS measurements show that low power and prolonged reaction time are sufficient, to significantly alter the chemical structure of lignin. The nonequivalent, High Resolution (HR), C-1s XPS analyses reveals the diversity of oxygen-based functionalitics. Besides the characteristic lignin functionalities, the existence of a newly formed -COO group can be noted. It has been suggested that the increase of -COO concentration is related to the diminution of C-C & C=C, C-O-C & C-OH, and O-C-O groups on the lignin structure.