The invention belongs to the technical field of pesticide synergism, and in particular relates to a synergistic weeding composition containing 1-(2-chloro-3-(3-cyclopropyl-5-hydroxyl-1-methyl-1H-pyrazole-4-carbonyl)-6-trifluoromethylphenyl) piperidine-2-ketone or a salt and ester thereof. The synergistic weeding composition contains a weeding effective quantity of active ingredients A and B, wherein A is a compound shown in the specification or a salt thereof, C1-C4 carboxylic ether, and benzoate; and B is selected from 1) phenoxy carboxylic acids, 2) pyridine carboxylic acids, 3) benzoic acids, 4) nitriles, 5) triazolinones, 6) diphenyl ethers, 7) thiadiazoles, 8) pyrimidine diones, 9) amides, 10) sulfonylureas, 11) slalfamides, 12) pyrazoles, 13) thiocarbamates, 14) bentazone and the like. The composition can effectively prevent and remove grassy weeds and broadleaf weeds in a wheat paddock, and has the characteristics of expanding a weeding spectrum, being obvious in synergistic effect, reducing the application amount, being safe to crops, and the like.