Objectives: To study the relationship between plasma oxidized low-density lipoprotein (ox-LDL) and carotid plaque, including plaque stability, of patients with acute ischemic stroke among Chinese Han ethnic group. Methods: A total of 181 patients with acute ischemic stroke were recruited and enrolled. The subjects were divided into a carotid plaque group and a no-plaque group by carotid ultrasound. The stability of carotid atheromas was assessed by ultrasound echo density, and the carotid plaque group was further divided into a vulnerable plaque group and a stable plaque group based on the echo results. Results: The study showed that the correlation between age [odds ratio (OR): 1.047; 95% confidence interval (CI): 1.014-1.082; P<0.01] and carotid plaque was significant. Plasma ox-LDL (OR: 1.020; 95% CI: 1.010-1.030; P<0.001) was also found to be significantly correlated with carotid plaque. Age was irrelevant to plaque stability (P=0.0685). The ox-LDL of the vulnerable plaque group was found to be significantly higher than that of the stable plaque group (P=0.015). By measuring the plasma ox-LDL in patients with ischemic stroke, the proportion under the receiver operating characteristic curve of vulnerable carotid plaques was 0.690 with a 95% CI of 0.613-0.767 (P<0.001). The point of cut-off was 94.5943, the sensitivity was 0.805, and the specificity was 0.505. Conclusion: The plasma ox-LDL level and age are possible risk factors for carotid plaque among patients with ischemic stroke of the Chinese Han ethnic group. This study suggests that ox-LDL could be used as a biomarker in screening for vulnerable carotid plaque in clinical practice.