Saccocoelium megasacculum n. sp. (Digenea: Haploporidae) was collected from the intestine of the mugilid fish, Liza carinatus (Cuvier and Valenciennes), in the Taiwan Strait. It is the first record of Saccocoelium in China. The parasite most closely resembles Saccocoelium obesum Looss, 1902 and Saccocoelium tensum Looss, 1902 in general morphology and body size, but it is easily distinguished from them in having a larger hermaphroditic sac in relation to body size; larger eggs; smaller pharynx, testis, ovary, and vitellaria; and a uterine seminal receptacle instead of a true seminal receptacle.