Objectives To investigate the relationship between cognitive impairment of elderly hemodialysis patients and serum hypersensitive C reactive protein (hs-CRP). Methods A cross-sectional study was performed in 119 hemodialysis patients to evaluate the cognitive function evaluated by Montreal Cognitive Assessment (MoCA) and serum hp-CRP level. A multi-logistic regression was performed to access the potential associated risk factor of cognitive impairments. Receiver operating characteristics (ROC) curve was also plotted to evaluate the diagnostic value of hs-CRP towards the cognitive impairment. Results 79 of 119 elderly hemodialysis patients aged from 60 to 86, whose MoCA scores were less than 26, and the prevalence of cognitive impairment was 66.4%.There were significantly older age, higher proportion of diabetes, lower education level, lower serum hemoglobin, albumin level and higher serum hs-CRP level in MCI groups (P < 0.05). Multi-logistic regression analysis showed that older age, lower educational status, diabetes, anemia, and the higher serum hs-CRP level were independently associated with cognitive impairment (P < 0.05). The area under curve of ROC analysis was 0.812 (95% CI (0.732, 0.892)), the cutoff point of serum hs-CRP under the maximum Youden index was 9.75 mg/L, and the sensitivity was 70.9% and the specificity was 82.5%. Conclusions Cognitive impairment is common in elderly hemodialysis patients. It might be associated with anemia, senior age, educational status and diabetics. High serum level of hs-CRP is also an independent risk factor for cognitive impairment, which may be an effective index for predicting cognitive impairment.