Organic residue analysis can provide direct evidence for the function of excavated vessels. “Yan” is one of the important utensils in ancient times. Its function was widely recorded, although residue analysis was rare. In this paper, the white grease residue found in the bronze vessel “Fu” (the lower part of the detachable “Yan”) from Xigou Village, Jiuquan, Gansu Province, was analyzed using infrared spectroscopy, fatty acid analysis and compoundspecific stable carbon isotope analysis to reveal the origin of the residue, as well as the function of the vessel. The results show that the white grease is probably ruminant adipose fat, which indicated that the residue was dripped oil caused by steaming beef or mutton in the “Zeng”. This study provides an evidence for the assembly of “Zengfu” as a steamer for meat processing, and also sugges a communication and integration in dietary culture between Han and northern nomadic people of the Wei and Jin dynasties, given that the tomb possesses a more nomadic style.