Abstract: Six trematodes of the family Bucephalidae were collected from freshwater fishes in Pearl River System of Guangdong Province, of these, two species are new to science. Type specimens are deposited in Biology Department of South China Normal University. The diagnosis of the new species are as follows:1. Bucephalus heptanematodes sp. nov. (Fig. 1)Body elongate, spinulate, 0.61—1.56×0.18—0.41mm. Rhynchus 0.12—0.25×0.11—0.20 mm, with seven tentacles at its end. Pharynx beside ovary, 0.06—0.11×0.06—0.14mm. Intestine extending anteriorly, 0.08—0.19 × 0.06—0.18 mm.Testes circular, tandem in posterior half of body, 0.10—0.28×0.10—0.18mm. Cirrus sac 0.22—0.61 × 0.05—0.12 mm, with anterior end reaching anterior end of anterior testis. Seminal vesicle round, 0.04—0.08 × 0.03—0.06 mm.Ovary oval, very close to anterior testis,0.10—0.20 × 0.10—0.18 mm. Vitellaria lateral, continous in fore body. Uterine coils between rhynchus and posterior end of body. Eggs small, 0.022—0.032 × 0.014—0.019 mm.The worm resembles B. uranoscopi Yamaguti, 1934 and B. polymorphus Baer, 1827. But differs from B. uranoscopr Yamaguti in the body length, in the size of eggs and in the extent of vitellaria. And it differs from B. polymorphus Baer in the position of pharynx, in the extent of vitellaria and in the size of cirrus sac.Specimens collected from the intestine of Mystus guttatus Lace. and Gobiabutia sp., Shaoguan, Guangdong Province, May, 1984.2. Prosorthynchus pentangularis sp. nov. (Fig. 2).Body fusiform, spinulate, 1.41—2.43 × 0.40—0.73 mm. Rhynchus with five head processes and four retractive fibres below, 0.17—0.29×0.32—0.50mm. Pharvnx to right of anterior testis, 0.10—0.17 × 0.10—0.16 mm. Intestine extending anteriorly, 0.11—0.27 × 0.15—0.32 mm.Testes oval or circular, diagonal in hind part of the body, 0.09—0.32 × 0.11—0.32 mm. Cirrus sac well developed, tubular, to right of the body with anterior end reaching anterior testis, 0.40—0.58 × 0.11—0.17 mm. Seminal vesicle sac-like, 0.18—0.24 × 0.04—0.06 mm.Ovary oval, very close to anterior testis, 0.10—0.20 × 0.10—0.21 mm. Vitelline glands comprise 20 to 28 round follicles, situated at fore body. Uterine coils between rhynchus and posterior extremity of body. Eggs small, 0.024—0.035 × 0.014—0.022 mm.Excretory vesicle "S"-shaped, extending anteriorly to rhynchus.The worm resembles P. crucibulus (Rud, 1819) Odhner, 1905, but differs from it in the shape of the rhynchus with five head processes, in the uterine loops extending anteriorly to the vitellaria and in the size of the uninary sac extending anteriorly to the rhynchus.Specimens collected from the intestine of Mystus guttatus Lace. and Pseudobagrus fulvidraco (Rich.), Shaoguan, Fengkai and Dongguan, Guangdong Province, September 1983.The new species are also observed with scanning electron microscope. The photographs and descriptions are included.