Based on a measurable range of optical emission spectroscopy (OES), the modeling of plasma characteristic is investigated depending on the position of incident angle of OES. In this work, OES is installed in the viewpoint of the plasma assisted atomic layer deposition (PA-ALD) system and plasma characteristic is measured using OES. For the enhancement to obtain the plasma characteristic information, the measurement scheme by inserting body tube in front of optical fiber is developed to receive the limited light of plasma. Since a normal optical fiber is not possible to measure plasma uniformity, the proposed scheme can measure a gap of plasma intensity for each region of a wafer. The detailed analytic model is developed by using the analysis between the plasma intensity and the characteristic of PA-ALD. This scheme can allow us to improve the accuracy of a plasma diagnosis, the detection capability of plasma abnormality and the manufacturability.