Objective:To correlate peripheral blood hypersensitive C-reactive protein (hs-CRP) with cognitive function in patients with depression.Methods:Seventy-five patients with depression who received treatment in the Second People's Hospital of Lishui from January 2019 to May 2020 were included in the depression group. An additional 50 healthy controls were included in the control group. The MATRICS Consensus Cognitive Battery (MCCB) was used to evaluate participates' cognitive function. Serum hs-CRP level was determined using enzyme-linked immunosorbent assay.Results:Speed of processing, working memory, verbal learning, visual learning and reasoning/problem-solving scores in the depression group were significantly lower than those in the control group ( t = 10.774, 2.774, 9.840, 5.064, 7.915, all P < 0.01). Serum hs-CRP level in the depression group was significantly higher than that in the control group [(13.05 ± 2.94) mL vs. (1.13 ± 0.18) mL, t = 28.595, P < 0.01]. Speed of processing, working memory, verbal learning, visual learning and reasoning/problem-solving scores in patients with moderate and severe depression were significantly lower than those in patients with mild depression. Serum hs-CRP level in patients with moderate and severe depression was (10.41 ± 2.21) mg/L and (25.71 ± 4.04) mg/L, respectively, which was significantly higher than that in patients with mild depression [(3.03 ± 0.49) mg/L, t = 3.015, 3.370; 3.903, 3.441; 3.541, 3.604; 4.503, 4.661; 4.001, 3.980; 4.035, 3.669, all P < 0.01]. Speed of processing, working memory, verbal learning, visual learning and reasoning/problem-solving scores in patients with severe depression were significantly lower than those in patients with moderate depression ( t = 8.331, 5.227, 10.031, 6.003, 9.416, all P < 0.01). Serum hs-CRP level in patients with severe depression was significantly higher than that in patients with moderate depression [(25.71 ± 4.04) mg/L vs. (10.41 ± 2.21) mg/L, t = 11.005, P < 0.01]. Pearson correlation analysis showed that serum hs-CRP level in patients with depression was remarkably negatively correlated with speed of processing, working memory, verbal learning, visual learning and reasoning/problem-solving scores (all P < 0.01). Conclusion:Serum hs-CRP level in patients with depression is greatly increased, can reflect the severity of depression and is related to cognitive function.