Objective To investigate the changes of serum high sensitive C-reactive protein(hs-CRP) level in patients with acute cerebral infarction(ACI),and the relationship between serum hs-CRP level and ACI severity as well as subtypes according to Chinese Ischemic Stroke Subclassification(CISS)criteria. Methods The serum hs-CRP level in 256 patients with ACI and 196 normal controls were measured. The degree of nervous function defect in patients with ACI was assessed by the United States National Institutes of Health Stroke Scale ( NIHSS ) score. All patients were classified into five major ischemic stroke subtypes based on CISS criteria. Logistic regression analysis was applied to analyze the risk factors of ACI. Results The serum hs-CRP level in patients with ACI and control group were(4. 69 ± 2. 58)mmol/ L and(2. 13 ± 1. 79)mmol/ L,and the difference between groups was significant(t = 12. 439,P = 0. 000). The hs-CRP in patients with severity ACI (147 cases)were(5. 89 ± 4. 15)mmol/ L,significantly higher than that in patients with mild ACI,and the difference between groups was significant((2. 11 ± 1. 45)mmol/ L,t = 10. 230,P = 0. 000)). As for subtype ACI,the case of the large artery atherosclerosis subtypes was 106( 41. 57% ),highest than any other subtypes. The hs-CRP level of large artery atherosclerosis was(7. 01 ± 3. 12)mmol/ L,higher than that of control group( P = 0. 000). The logistic regression analysis showed that many factors were related to ACI including total cholesterol,homocysteine and high sensitive C-reactive protein( OR = 0. 324,0. 749,0. 809;P< 0. 05). Conclusion The serum hs-CRP level in patients with ACI increase significantly,and relate to the degree of neural function defect. The level of hs-CRP of large artery atherosclerotic stroke is the highest. The change of serum hs-CRP is very valuable to estimate the severity of ACI.