As a raw material in the Xiangxi traditional food “Haocaibaba” (a very popular cake-like food from China), the application of Artemisia princeps has a long history in Xiangxi. In this study, the nutritional value and antioxidant activity of A. princeps, the raw material of “Haocaibaba”, were analyzed by means of routine physical and chemical analyses, and an in vitro antioxidant test. The content of protein, fat, and dietary fiber in A. princeps was higher than that of Oryza sativa, Solanum tuberosum, Brassica pekinensis, Spinacia oleracea, or Coriandrum sativum. A. princeps was rich in aspartic acid and glutamic acid and contained at least 18 amino acids. A. princeps contained a variety of minerals, of which the content of potassium was the highest, followed by 25 elements, such as calcium, magnesium, iron, aluminum, manganese, and sodium. Four vitamins were detected, including vitamins A, C, E, and B₂. A. princeps had the ability to clear 1, 1-diphenyl-2-picrylhydrazyl radicals (DPPH) and 2, 2′-amino-di (3-ethylbenzthiazoline sulphonic acid-6) ammonium salt cationic radicals (ABTS⁺•), to delay the carotene fading, and to inhibit lipid peroxidation. These results confirm that it is a very reasonable choice for the Xiangxi people to make “Haocaibaba” using A. princeps.