Objective To explore the efficacy and safety of 70% ethanol lock for the prevention of catheter related blood stream infection (CRBSI) in maintenance hemodialysis (HD) patients with a tunnel cuffed central venous catheter. Methods A randomized self-crossover controled method was used in this study. A total of 32 HD patients with tunnel cuffed catheters, from the Department of Nephrology of Zhongda Hospital of Southeast University, were randomly assigned to ethanol lock group (the patients received 3.3 mL 70% ethanol lock once a week and 3.3 mL standard heparin lock twice a week) and heparin lock group (the patients received 3.3 mL standard heparin lock three times a week), each group with 16 patients, and the lock methods of two groups were exchanged after locking for 22 weeks. We then analyzed and compared the incidences of CRBSI, catheter dysfunction and another adverse reactions of the patients in two groups. Results Two patients withdrew from the study, two died, and totally 28 patients fully participated in the study, with each group haviny 14 patients. The incidence of CRBSI was 0.45 per 1 000 catheter-days in ethanol lock group and was 0.92 per 1 000 catheter-days in heparin lock group, showing significant difference between the two groups (P> 0.05). There was no significant difference in the incidence of catheter dysfunction between the ethanol lock group and the heparin lock group (0.90 per 1 000 catheter-days vs 2.06 per 1 000 catheter-days; P> 0.05). There were no significant differences in routine blood test, liver function or coagulation function between the two groups. The patients in the ethanol lock group were not observed with adverse reactions, including nausea, vomiting or dizziness. Conclusion The incidence of CRBSI has been declining in the maintenance HD patients with a tunnel cuffed catheter in the ethanol lock group, although it is not significantly different from the heparin lock group.