Objective To investigate the impact of Coronavirus Disease 2019 (COVID-19) on long-term renal function in patients with chronic kidney disease (CKD) who received no renal replacement therapy. Methods Thirty-nine CKD patients with an estimated glomerular filtration rate (eGFR) < 60 mL/(min·1.73 m²) at the time of COVID-19 diagnosis, admitted to Guizhou Aerospace Hospital from December 2022 to March 2023, were enrolled in the COVID-19 group. Additionally, 40 CKD patients without COVID-19 from September to December 2021, were included in control group. Changes in eGFR were compared between the two groups, and the temporal trend of eGFR in the COVID-19 group was analyzed using a mixed-effects linear model. Results No statistically significant differences were observed in eGFR levels at baseline, 1- and 3-month of follow-up between the COVID-19 and control groups (P>0.05). However, at 1 year of follow-up, the eGFR level in the COVID-19 group was significantly lower than that in the control group (P < 0.05). The mixed-effects linear model analysis revealed a decrease in eGFR by 1.84 mL/(min·1.73 m²) within 1 year of COVID-19 onset in the COVID-19 group, which inclined 4.62% from baseline, with the most significant decline (7.45%) observed among diabetic patients. Conclusion Patients with CKD who have not undergone renal replacement therapy experience a substantial decline in eGFR and worsened renal function within 1 year of COVID-19, necessitating close long-term renal function monitoring and timely interventions.