Abstract: A peculiar fluke, Paragonimus jiangsuensis sp. nov was discovered in the mountainous region of southern Jiangsu from 1980 to 1981. The worm body is elongated, the ratio of length to width being 2.65:1. Cuticular spines are singly spaced under the scanning electron microscope. The oral sucker is somewhat smaller than the ventral sucker which is located in the fluke body about 1/3 of its length from anterior extremity. Ovary is seen clearly to have rich grade branches (about 3-4) and it is coral-shaped. The testis is smaller than the ovary, being less than 1/9 of the body size. Like the ovary, it also has multi-branched lobes; The metacercaria, elliptical in shape and 494.76 × 82.53 by 446.85 ×74.57 μm in size is enclosed within two thin layers of cyst wall. Sinopota-mon yangtsekiensis is believed to be the second intermediate host, but the snail host, reservoir host, or a human infection with the new species is unknown at present.