The invention discloses a ternary weeding composition containing diflufenican and application thereof. The effective active ingredients are prepared from a first active ingredient of diflufenican, a second active ingredient of florasulam and a third active ingredient of flufenacet; the mass ratio of the three ingredients is (1 to 90):(1 to 90):(1 to 90), is preferably (1 to 60):(1 to 60):(1 to 60), is further preferably (1 to 30):(1 to 30):(1 to 30) and is most preferably 15:2:18. The composition can be prepared into agriculturally allowable suspensions, dispersible oil suspensions, wettable powder and water dispersion particles. The ingredients are reasonable; the weeding effect on broad leaved weed in cornfield is good; the active and weeding effects are not simple addition of activity of each ingredient. Compared with the existing single preparation or two-ingredient compound preparation, the ternary weeding composition has the advantages of obvious weeding effect, obvious synergized action, reduced pesticide consumption, wide weeding spectrum and low prevention and control cost.