Hermaphroditic planarians possess a very important position in systematic evolutionary history of animals,and have a powerful capacity of complete regeneration.The histological structure of reproductive system of Dugesia japonica is revealed with H.E method,Masson method and Van Gieson method.The results show that sexual planarians are hermaphrodites.Both the male reproductive system and the female one consist of reproductive glands and tubes.Female reproductive gland is composed of the ovary,the yolk gland and the copulatory bursa.Female reproductive tube includes the oviduct and the bursa stalk.The male reproductive gland is mostly composed of testes.Male reproductive tube includes the spermiducal vesicle,sperm duct,bulbar cavity,and ejaculatory duct.The copulatory bursa is made up of simple columnar epithelium:the cytoplasm is strongly basophil,the nucleus is located at the basal face of the epithelium,and many vesicular structures exist at the free face.The yolk gland belongs to unicellular gland like a bulb:its nucleus is smaller and situated at its handle.Thereby,it is identified that the copulatory bursa possesses the exocrine function.The number of the yolk gland represents periodism.