Morphology and histology of the digestive system of Capitulum mitella were observed by light microscopy. The results showed that the digestive system consisted of digestive gland and digestive tract. A pair of long cystic digestive glands contained four types of cells: secretory cells, resorptive cells, inocyte cells and embryonic cells. The digestive tract consisted of mouth, esophagus, stomach, gut, rectum and anus. The mandibulate mouthpart comprised of a labrum, two palpuses, two mandibles and four maxillas. From inner to outer, the wall of the digestive tract was divided into four layers: mucous layer, submucous layer, muscular layer and outer membrane. The wall of the thin and short oesophagus was lined with cuticle without basement membrane and possessed a layer of thick circular muscle and radiating muscle. The stomach was sacculate, and the gut was the longest in the digestive tract. Histological structure of the stomach and the gut was similar to each other. Both of them lacked cuticle, and their epithelium cells were covered with well-developed microvilli. The rectum was slender. The most obvious difference between the rectum and other parts was that 16 groups of longitudinal muscle distributed in its outer membrane. Histological structure of the anterior rectum, covered with well-developed microvilli, was similar to that of the stomach and the gut. The wall of the posterior rectum gradually degraded, but 16 groups of longitudinal muscle in its outer membrane gradually developed. The anus possessed well-developed longitudinal muscles and circular muscles which circled around outside of the anal wall. Histological structure of C.mitella in various parts of the digestive tract was different, reflecting differences in their functions.