The present invention relates to a composition comprising shikonin compounds, especially, isobutyryl shikonin, .beta.-.beta.-dimethylacryl shikonin, isovaleryl shikonin, and .alpha.-methyl-n-butyryl shikonin as an active ingredient for the prevention and treatment of diabetes mellitus and the use thereof. The composition of the present invention showed stimulating effect on the release of insulin in the beta cell of the pancreas due to inhibitory effect on K.sub.ATP ion channel of beta cell in pancreas together with promoting effect on the increase of calcium concentration. Therefore, it can be used as the therapeutics, health functional food or food additive for treating and preventing diabetes mellitus.