Acetochlor is a widely used herbicide in agricultural production.Studies have shown that acetochlor has obvious environmental hormone effects,and long-term exposure may pose a threat to human health.To quantify the hazards of acetochlor in drinking water,a health risk assessment of acetochlor was conducted in major cities of China based on the data of acetochlor residue concentrations in drinking water.The approach of the Species Sensitivity Distributions (SSD) method is used to extrapolate from animal testing data to reflect worst case human toxicity.Results show that hazard quotients related to acetochlor residues in drinking water for different age groups range from 1.94 × 10-4 to 6.13 × 10-4,so,there are no indication of human risk.Compared to the total estimated hazard quotient from oral intake of acetochlor,the chronic exposure imputed to acetochlor residues in drinking water in China accounts for 0.4％.This paper recommends 0.02 mg/L to be the maximum acetochlor residue concentration level in drinking water and source water criteria.