Ketoclofen is a new Post-Seedling herbicide with excellent selectivity. It is suitable for broad-leaved fields such as soybean, rape, cotton and peanut to control barnyard grass, wild oat, horse tang, setaria, tendon grass, maidenhair, bluegrass, hard grass and other grass weeds. After application, it can be quickly absorbed by the stems and leaves of Gramineae weeds and transmitted to the shoot tips and tissues, inhibit the activity of meristem, destroy cell division, and eventually lead to weed death.