Abstract: The Weijiawopu site is located in Weijiawopu village in the city of Chifeng, Inner Mongolia. This site is a Ring Trench Settlement, which belongs to the Middle period of Hongshan Neolithic Culture. During the 2009-2011 excavation, many pottery flat-bottom tanks were unearthed with dark ash inside, which was collected for the plant residue analysis. Tanks without dark ash were also examined for the surface residues. From six specimens, starch grains were found after the laboratory processing. These starch grains could be classified into four groups, and identified to be from millet, plant underground storage organ, possibly nut and unidentifiable species. The tanks are thus speculated to be utensils for food stuff, for storage or transportation. The existence of plant underground storage organ indicates that the Weijiawopu occupants still gathered wild plants during the occupation time when they already domest icated crops.

Key words: Inner Mongolia; Weijiawopu site; Hongshan Culture; Millet; Starch grain