The invention discloses a 1, 2, 4-triazine-coumarin compound and a preparation method and application thereof. The compound is of the structure as indicated in the formula (I), and the preparation method comprises the steps that 7-umbelliferone and epoxy chloropropane serve as raw materials, 7-(oxirane-2-methoxyl)-2H-benzopyran-2-ketone is obtained, 1, 2-diphenylethane-1, 2-diketone and thiosemicarbazide serve as raw materials, 5, 6-diaryl-1, 2, 4-triazine-3-thioalcohol is obtained, and finally 7-(oxirane-2-methoxyl)-2H-benzopyran-2-ketone reacts with all types of 5, 6-diaryl-1, 2, 4-triazine-3-thioalcohol, so that the target compound is obtained. The compound can serve as the raw material of anti-diabetic medicine, the preparation method is simple, raw materials are easy to obtain, and operation is convenient.