ln order to avoid the potential safety hazards caused by liquid chlorine disinfection. the chlorination disinfection system upgrade project of a water plant in a national development zone in Jiangsu was taken as the research object. Sodium hypochlorite was used instead of liquid chlorine as disinfectant. The disinfectant consumption, residual chlorine and disinfection by-products using liquid chlorine and sodium hypochlorite were compared. The results showed that there was no significant difference in the effect of reducing turbidity and removing residual chlorine using these two disinfectants. With the same treatment effect, the average chlorine consumption of sodium hypochlorite and liquid chlorine were 14.71 kg/kt and 1.47 kg/kt, respectively. Disinfecting with liquid chlorine and sodium hypochlorite, the mean values of THMs were 379 μg/L and 253 μg/L, respectively. Compared with liquid chlorine disinfection, sodium hypochlorite disinfection process reduced the production of disinfection by-products.