Abstract: To investigate the effect of vitamin D on cognitive function in mice with chronic kidney disease(CKD) induced by adenine. Methods: Fifty-six male C57 BL/6 J mice were randomly divided into five groups: control(CON), model(CKD), and low, medium and high vitamin D(LVD, MVD and HVD) supplement. The renal failure was induced in mice by chronic dietary adenine intake. Mice in the vitamin D-treated groups were injected with calcitriol(20, 100, 500 ng/kg) three times a week for six weeks. Then, blood samples were collected from the orbit, and serum creatinine, urea nitrogen and the activity of superoxide dismutase(SOD) were detected. Pathological changes were observed using HE and Masson staining. The cognitive function was assessed using the Morris water maze. Results: Compared with CON group, serum creatinine and urea nitrogen increased in CKD group(P<0.05). Kidney damage such as glomerular atrophy, renal interstitial fibrosis could be observed in CKD group. In the probe trial testing, compared to CON group, the escape latency of mice in CKD group was longer(P<0.05). And the escape latency of MVD and HVD group was shorter than that in CKD group(P<0.05). In the hidden-platform trial, time and travel distance spent in the goal quadrant in CKD group was lower than that in CON group(P<0.05), and the time and distance in MVD and HVD group was higher than that in CKD group(P<0.05). The activity of SOD decreased in CKD group compared to CON group(P<0.05), and increased in LVD and MVD group compared to CKD group(P<0.05). Conclusion The cognitive function of CKD mice descends. Vitamin D can improve cognition in CKD mice through its antioxidant function.