The objective assessment algorithm Structural Similarity(SSIM) of image quality was not consistent with the Mean Opinion Score (MOS) in particular types of distoration, such as seriously blurred type, etc. In this paper, three models Edeg-based SSIM, HVS-based SSIM, and IW-SSIM which had considered the characteristics both of HVS and structural information were compared in evaluating the seriously Gaussian blurred images. The experimental datas showed that, the IW-SSIM's monotony perfomance was more stable than other models in the relationship between the subjective and objective values, as well as the growing accuracy of the ESSIM and HSSIM. These experimental results are benefit for improvingt the SSIM approach.