Objective To investigate the Anisakis sp. 3^rd stage larvae infection of Pneumatophorus japonicus in the Yellow Sea area. Methods 113live fish(15-20per month)of Pneumatophorus japonicus were collected from the Yellow Sea area during May 2010and January 2011,then dissected to examine and record the quantities of nematodes in the coelom,visceral organ,back muscle, abdominal muscle and tail muscle, respectively. All nematodes transparented by iactophenol clearing solution were identified by morphology, and 192of them(30-35per month)were classified by PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism). Results 86.7% of 98fish were infected with Anisakis sp. 3^rd stage larvae. A total of 4770larvae were collected with the infection intensity of 5-194per fish and the average of 42.2per fish. 88.7% (4229/4770) of the larvae were detected in the coelom and visceral organ, while 87.2% (470/539) from body muscles were founded in the abdomen. The infection intensity rose up with the increase of body weight. The larvae observed were all Anisakis type I and 192of them were classified as A. pegrefii (191) and A.typica(1). Conclusion The Anisakis sp. 3^rd stage larvae infection of P. japonicus was serious which correlated with season, body weight and different body parts. The infection was identified as A. pegrefii by RFLP. The results could provide references to healthy quarantine and fisheries. \=