Abstract: Green house study was carried out to investigate the effect of humic acid on the uptakeing and removal of prometryn from hydroponic media by vetiver grass. GC-MS (Agilent 7890B-5977MSD, USD) was used for qualifying and quantitying theprometryn from the solution and plant samples. The results showed that humic acid (200 mg/L) had no significant effect on the absorption and removal of prometryn from the nutrient solution by vetiver grass, but the initial concentration of humic acid 200 mg/L could significantly promoted the absorption of prometryn by the roots of vetiver grass, and inhibit prometryn from the roots of vetiver grass transferd to the shoots significantly.