The invention discloses an application of a 3-(1,5-diphenyl-4,5-dihydro-1H-pyrazole-3-group)-7-hydroxyl-2H-chromene-2-ketone in the preparation of a drug for stabilizing an arteriosclerosis plaque, wherein the dose of the 3-(1,5-diphenyl-4,5-dihydro-1H-pyrazole-3-group)-7-hydroxyl-2H-chromene-2-ketone for effectively stabilizing the arteriosclerosis plaque is 1 mg/kg/day. The experiment proves that the 3-(1,5-diphenyl-4,5-dihydro-1H-pyrazole-3-group)-7-hydroxyl-2H-chromene-2-ketone has the advantages of being capable of significantly reducing the apoptosis rate of endothelial cells in aortic plaques and the apoptosis rate of cells in aortic root plaques; improving the structure of the plaques; improving the stability of the plaques; being capable of being used as an effective tool for studying an unstable molecular mechanism of the atherosclerosis plaque; laying a groundwork for developing the drug to treat arteriosclerosis.