This paper deals with the acanthocephaliasis of carp. The work wascarried out in 1985-87 at the Third Xinmin Fishfarm of Chongming County. 233diseased fish were vivisected and 964 parasites were observed. The detail of taxologicalcrucial characteristics were checked with scanning electron-microscope. The parasiteis a new species of genus Rhadinorhynchus in family Rhadinorhynchidae. This newspecies was designated Rhadinorhynchus chongmingnensis sp. nov. The pathogen, symptom and therapy of this disease are presented as follows: 1) Pathogen: Rhadinorhynchus chongmingnensis sp. nov. The male of adultparasite is 18.25mm in average length and 1.75mm in average width, the femaleaverage length is 23.59mm and 2.58 mm in average width. All over the proboscisare covered with fine fur. The crucial characteristics of this new species are 14longitudinal rows of 29-32 hooks on the proboscis. (see table 4 in the paper). The type specimen were preserved in The Fish Disease Laboratory, ShanghaiFisheries University. 2) Symptom: The disease is not very serious at all. When once a fish carries alot of parasites, it will cause death. The parasite mainly lives in the digestive tractof fish. After the probosics bores into the intestines wall, the granuloma will formaround the worm. This disease can infect to carp of size from 9-2,050 grammes. Itwould damage 60%, if 100% of fish are infected. 3) Therpy: The daily dosage is 0.6ml carbonei tetrachloridum per kilogram offish weight, mixed in fish food. Generally, if continually treating for six days, asatisfactory curative effect would be obtained.