Abstract: 【Abstract】 Objective To investigate the effect of different kind of disinfections for dialysis water supplying system. Methods We tested and compared the amount of bacteria and endotoxin in water by using the chemical (formaldehyde) disinfection, and heat sterilization with the heat frequencies of once every day, every 3 days and every week.  Results The amount of bacteria and endotoxin were 38.90±36.32 CFU/ml and 0.42±0.38 EU/ml, respectively, in water with heat sterilization, and were 42.67±39.04 CFU/ml and 0.42±0.38 EU/ml, respectively, in water with chemical disinfection, without statistical differences in amount of bacteria and endotoxin between the two methods. The amount of bacteria and endotoxin were 38.27±37.11 CFU/ml and 0.42±0.38 EU/ml, respectively, in water with heat sterilization once a day, 39.11±34.18 CFU/ml and 0.39±0.35 EU/ml, respectively, in water with heat sterilization once every 3 days, and 42.08±39.87 CFU/ml and 0.42±0.41 EU/ml, respectively, once every week, without statistical differences in amount of bacteria and endotoxin among the three methods. Conclusion It is effective and simple for dialysis water supply system to use heat sterilization combined with intermittent formaldehyde chemical disinfection.