A new species of cyprinid fish genus Sinocrossocheilus has been recognized on basis of collections from Hongshuihe River, a tributary of Xijiang, Guangxi, China, September, 1993. All type specimens of Sinocrossocheilus megalophthalmus sp. Nov. (Holotype: KIZ 9309011, 49.1 mm SL) were collected from an underground river of Hongshui He in Tian-E County, Guangxi, China. S. megalophthalmus sp. Nov. is closely related to S. guizhouensis, S. microstomatus and S. labiatus by having 2 rows of pharyngeal teeth, while the other 7 species of the genus having 3 rows. It can be distinguished from S. guizhouensis by following characters: no black spot above midpoint of pectoral fin vs. having a prominent black spot; branched dorsal fin ray 7 vs. 8; branched pelvic fin ray 7 vs. 8; predorsal scales 15-16 vs. 12-14; bigger eye, eye diameter 2.5-3.1 in head length vs. 4.0-5.0; eye diameter 44.7%-57.8% head width vs. 16.6%-20.7%; rostral barbel reaching between anterior and posterior nostrils or reaching anterior edge of eye vs. not reaching posterior edge of posterior nostril; maxillary barbel reaching between anterior edge of eye and midpoint of eye or reaching between midpoint of eye and posterior edge of eye vs. reaching anterior edge of eye; caudal peduncle depth 8.9-10.7 times in SL vs. 7.2-8.2; snout length 2.5-3.7 times in head length vs. 1.9-2.2. It can be distinguished from S. labiatus by following characters: predorsal scales 15-16 vs. 22; lateral line scales 39-40 vs. 42-45; scales above lateral line 4.5-5.5 vs. 6.5; branched dorsal fin rays 7 vs. 8; gill rakers 13 vs. 10; pelvic fin reach anus vs. not reach; eye diameter 44.7%-57.8% head width vs. 23.3%-30.0%. S. megalophthalmus is most similar to S. microstomatus in fin ray counts, lateral line scales and color pattern, but it can be distinguished from S. microstomatus by following characters: circumpeduncle scales 14/16 vs. 12; bigger eye, eye diameter 2.5-3.1 times in head length vs. 4.4-4.6; pelvic fin reaching anus vs. not reaching anus; maxillary barbel reaching between anterior edge of eye and midpoint of eye or reaching between midpoint of eye and posterior edge of eye vs. reaching below eye; prefringe of rostral cap split into fimbriations vs. not split or not prominent split; dorsal fin origin closer to snout tip than caudal fin base vs. equal to; dorsal fin longer than head vs. almost equal to; caudal peduncle length 4.8-5.9 times in standard length vs. 6.1-6.4; snout length 2.5-3.7 times in head length vs. 2.1-2.4; caudal peduncle length 1.6-2.1 times its depth vs. 1.4-1.5.