In this paper, we perform the comparison of the quality degradation between the coded stereo-scopic image and its 2 dimensional image. This comparison was based on MOS (Mean Opinion Score) which is obtained from the subjective evaluation experiment. The evaluation experiment of the 2 dimensional image was investigated for 3-D display sytem which was the same as the evaluation experiment of the stereoscopic image the quality evaluation model of the stereoscopic image (PQS_<stereo>) by using the result of the subjective evaluation experiment.