Objective To study the relationship between cognitive dysfunction and location of lesion and prognosis in patients with cerebral infarction.Methods 120 patients with cerebral infarction in the Second People's Hospital of Yueqing were selected.According the results of the cerebral CT or MRI,the patients were divided into primary group(58 cases)and recurrence group (62 cases).3 -10days after admission,the cognitive impairment was evaluated with the method of simple mental state examination (MMSE)scale.The stroke score of the National Institutes of health(NIHSS)in the United States and ability of daily life activity Barthel index score before the admission and after the discharge were conducted on the patients.And the relationship between different lesion location of primary or recurrent infarction,cognitive disability and prognosis were observed.Results The incidence of cognitive impairment in the ecurrence group was 90.32%,which was obviously higher than 72.41% in the primary group(χ2 =6.419,P =0.011);In the two groups,the proportion of thalamic cortex was the highest,but there was no significant difference between the two groups (χ2 =0.000,P =1.000).The NIHSS and Barthel scores of patients with thalamic infarction were (11.4 ±1.6)points and (27.5 ±3.7)points respectively,both of which were the highest(FNIHSS =47.22, PNIHSS =0.000;FBarthel index =17.77,PBarthel index =0.000);the NIHSS and Barthel indexes in each part of the two groups at discharge were lower than those before the admission (all P <0.01),and the differences at admission was not statistically significant(P >0.05);the NIHSS scores of the primary group and the recurrent group at discharge were (6.3 ±0.5)points and (7.8 ±0.7)points respectively;the Barthel scores were (24.3 ±7.3)points and (30.8 ± 6.8)points respectively.And all of them were lower than those at admission and the improvement degree of the primary group were more significant than those of the recurrence group(tNIHSS =13.43,PNIHSS =0.000;tBarthel index =5.05, PBarthel index =0.000).Conclusion Cognitive impairment after cerebral infarction is associated with lesion,and thalamic infarction is the most prone to perform cognitive disfunction with poor prognosis,and the frontal and temporal lobe are also common parts where targeted prevention is needed.