Abstract: Stereoscopic image quality assessment（SIQA） is an important criterion for evaluating distortions in the coding and transmission of stereoscopic image/video systems.Considering the change of image structure information reflects the distortion of stereoscopic images,an objective SIQA（OSIQA） model based on the structure distortion analysis is proposed in this paper.OSIQA combines left-right image quality assessment（LRIQA） with depth perception quality assessment（DPQA）.Based on the facts that different regions of an image have different sensitivities,and natural images have direction singularities,the qualities of the left and right views are assessed and further linear weighted to evaluate structure distortion of each view.Moreover,distortion in depth perception is measured with singular value vector and mean error rate with respect to the difference map of the left and right views.Finally,the above two assessing results are combined to describe the quality of the stereoscopic image.The experimental results show that the correlation coefficient（CC） values between the proposed OSIQA model and subjective perception are higher than 0.93 in five distortion types,including Gaussian blur,Gaussian white noise,JPEG,JP2000,and H.264 encoding.Spearman rank order correlation coefficients（SROCC） are higher than 0.92,rooted mean squared error（RMSE） values are lower than 6.6.It means that the proposed OSIQA model is highly consistent with the subjective assessment.