Abstract: Objective To explore the risk factors of cerebral microhemorrhage(CMB) in patients with acute ischemic stroke and the correlation between the level of serum cystatin C(Cys-C) and the severity of CMB. Methods From October 2016 to July 2019, 120 patients with acute ischemic stroke hospitalized in the Department of Neurology of Beilun District People's Hospital were selected. After 7 days of hospitalization, MRI-SWI sequence was performed. According to the results, the patients were divided into CMB group(39 cases) and non-CMB group(81 cases). The differences of clinical data and test results between the two groups were compared. Taking statistically significant variables as independent variables, multivariate logistic regression was used to analyze the risk factors of CMB, and Spearman correlation was used to analyze the relationship between Cys-C level and the number of CMB. Results The age, SBP, DBP and hs-CRP of CMB group were higher than those of non-CMB group(all P<0.05). The Cys-C level of CMB group was(1.23±0.11) mg/dL, and that of non-CMB group was(1.02±0.11) mg/dL, the difference was statistically significant(t=9.754, P<0.05). The eGFR level of CMB group was(63.52±18.02) mL/(min·1.73 m²), and that of non CMB group was(76.44±18.42) mL/(min·1.73 m²), the difference was statistically significant(t=3.624, P<0.05). The result of Multivariate logistic regression showed that SBP, eGFR, Cys-C were independent risk factors of CMB in patients with acute ischemic stroke, and the Spearman correlation analysis showed that Cys-C level was positively correlated with the number of CMB(r=0.482, P<0.001). Conclusion Serum Cys-C has a positive correlation with CMB in patients with acute ischemic stroke, which can be used as an independent risk factor for CMB.