Abstract:Yenan site is located at Yenan village of Yicheng county, Shanxi province, and the remaining area of the site is about 1.2 km2, which dates back to the West Han Dynasty. The matrix compositions and microstructures of 6 slag samples and 2 metal iron block samples collected from Yenan site were analyzed by means of X-ray fluorescence analyzer (EDX), scanning electron microscope and energy spectrum analyzer (SEM-EDS) and metallographic microscope. The results show that the 6 slag samples are Si-Ca-Al low-iron slags, and the 2 metal iron block samples are wrought iron, which should likely be products of puddling steel. Yenan iron smelting site is a cast iron smelting site, while it is also a puddling steel site. The site is the first large-scale puddling steel smelting site and official site of the Han Dynasty in Shanxi province that has ever been confirmed.