Sethoxydim, a molecular formula of C17H29NO3S, is a highly selective, internal-conveying stem and leaf treatment agent that can be rapidly absorbed by the stems and leaves of grass weeds and transmitted to the apical and internode meristems, causing cell division. Damage to death. Can be used for soybeans, cotton, rapeseed, peanuts, potatoes, beets, sunflowers, flax and other crops and orchards, control valerian, wild oats, Setaria, aunt, crabgrass, goosegrass, etc., are not effective against broad-leaved weeds. For the control of weeds in soybeans and cotton, water is sprayed with 20% EC at 10-20 mL/100 m2 and 8-15 mL/100 m2, or with 5% oil EC at 10-15 mL/100 m2.