Abstract：Objective This study intend to explore the correlation between stroke and the ratio Q, Gray-scale median(GSM)/total plaque volume(TPV) by using three-dimensional ultrasonography. Methods Firstly, we will randomly select 149 patients with carotid plaque in neurology, and further removing 17 patients whose plaque are too deep-rooted that cannot be detected with QLAB-VPQ, and 25 patients without brain images. The rest 107 patients become the testing samples. The testing participants will be divided into two groups according to their brain scanning images results of CT,MRI and etc. After this step, 66 patients divided into group A, labeled as Group Stroke, and 41 patients dived into group B, labeled as Group Non-stroke. All participants will be tested to get their Ratio Q, which is the value of Gray-scale Median (GSM) tested with the aid of QLAB-VPQ, and Total Plaque Volum (TPV). A methodological statistics will be applied to analysis the correlation of ration Q with stroke. Results Firstly, the rank-sum test of the ration Q of group A and group B, the statistic Z= - 4.857, and P = 0.000, and the difference is statistically significant; secondly, the OR of ratio Q is calculated as 1.015 CI (1.007-1.024) after a unconditional logistic regression analysis of ratio Q. In this way, ratio Q could be categorized as a correlated risk factor to stroke. Conclusions ratio Q is negatively correlated with stroke, in other words, the lower the Ratio Q is, the higher the risk of occurring stroke, and vice versa.