The invention discloses a weeding composition containing penoxsulam, mesotrione and pretilachlor and an application therefor. The weeding composition comprises a first active ingredient penoxsulam, a second active ingredient mesotrione and a third active ingredient pretilachlor in a weight ratio of (0.1-90): (0.1-90): (0.5-90), preferably (0.2-50): (0.2-50): (2-50). The composition can be prepared into agriculturally permissible suspensions, dispersible oil suspensions, suspoemulsions, emulsion oil, microemulsions, wettable powder, water dispersible granules, granules, tablets and effervescent tablets. The weeding composition disclosed by the invention is reasonable in composition, good in weeding effect and low in medicinal cost. The activity and weeding effect are not simple superposition of activity of the ingredients. Compared to an existing single preparation, besides the remarkable weeding effect, the weeding composition further has a remarkable synergistic effect, delays the resistance, is good in safety, and meets the safety requirements on pesticide preparations. The weeding composition disclosed by the invention has a good preventing and treating effect on northeastern transplanted paddy field weeds: barnyard grass, lecrsia oryzoides, scirpus tabernaemontani, sagittaria trifolia, rhizoma alismatis and the like.