Abstract: Embodiments of the present invention relate to use of a GP73 inhibitor in preparation of a drug for treating diabetes. In the embodiments of the present invention, the inventor finds that GP73 plays a key role in blood glucose regulation, and in particular, finds that soluble GP73 can specifically bind to glucagon to form a complex, enhances the blood glucose-rising function and gluconeogenesis function of glucagon and prolongs the half-life of glucagon; and finds soluble GP73 can activate the glucose production in liver and/or kidney and a gluconeogenesis signaling pathway in a glucagon-independent manner. Based on the blood glucose regulation effect of the GP73 described above, the inventor also proves through animal experiments: the GP73 inhibitor can reduce the blood glucose level and glycated hemoglobin level of diabetic mice and have a protective effect on islet ? cells, and thereby having the effect of treating diabetes.