Abstract: This paper reports on the etiology of paragonimiasis studied from August to De Member 1981 in Tongkwan, Changan and Huxian region of Shaanxi Province. Metacer cariae were found in 51 crabs examined. They were 417.9 x 404μm in average and the ventral sucker is larger than the oral sucker. Of the 84 adult lung flukes obtained from the lungs of one cat, three dogs and two white rats after being fed metacercariae, 20 were identified. The adult lung flukes obtained from dogs were 9.53mm in average length, 3.75mm in width, the width to length ratio being 1:2.54. The ventral sucker is situated at the anterior 1/3 of the parasite. The oral sucker is smaller than the ventral sucker. The cuticular spines are blunt in shape, and of sin'gle growth arrangement. The ovary is more branched. The testes are slender with few branches and situated in the posterior 1/2 of the worm. The ovum contains 6-7 yolk cells. The average size of 142 ova measured is 69.9 by 44.6μm. There is a short spine at the posterior end of some ova. Thus, the species of lung fluke in Shaanxi Province is Pagumogonimws skrjabini Chen 1959.