Stereoscopic image quality assessment is an effective way to evaluate the performance of stereoscopic video system.However,how to utilize human visual characteristics in quality assessme nt is still an issue.In this paper,considering the characteristics of gradient s tructure tensor in image feature description,an objective stereoscopic image quality assessment method based on three-dimensional (3D) structure tensor is p roposed.To be more specific,we obtain the horizontal,vertical and inter-view gradient information for each pixel in the original and distorted stereoscopic images,and construct the 3D structure te nsor.Then,the corresponding eigenvalues and eigenvectors are extracted from the 3D structure tensor.Finally,according to the eigenvalues and the eigenvectors,th e values of objective assessment between the original and distorted stereoscopic images are predicted.Experimental results d emonstrate that compared with other methods,the overall Pearson linear correlation coefficient (PLCC) and the Spearman rank order correlation coefficient (SROCC) indicators reach 0.92,the Kendall rank-order correlation coefficient (KROCC) indicator reaches 0. 80,and the root mean squared error (RMSE) indicator is approxim ately 6.00,w hich indicates that the proposed method can achieve higher prediction accuracy.