A new species of Proteocephalus from the fish Sinocyclocheilus grahami tingi, a subspecies endemic to Fuxian Lake in Southwest China, is described.This is the first report of cestode from this host. The new species differs from P. exiguus, P Longicollis, P parasiluri and P. torulosus,the only other species of Proteocephalus currently reported from China, by lacking an apical sucker from P. exiguus by having 45- 108 rather than 24-54 testes per proglottis, and a maximum of 15 rather than 28 uterine diverticula,from P. longicollis by having an average of 45- 108 rather than 75-115 testes per proglottis and testes being in a single layer instead of 2 layers; and from P. torulosus by having 45-108 instead of 150 testes per proglottis and testes being in 3-4 layers; and from P. parasiluri by having 45-108 rather than 180 testes per proglottis. It resernbles P. percae,P. pollanicola, and P. thymalli in number of testes and uterine diverticula, but differs by lacking an apical sucker. Proteocephalus thymalli, like the new species, has a vagina that opens dorsally to the cirrus sac, but P thymalli slao has postovarian testes,which the new species lacks. The possible significance of parasitological examinations of the other two subspecies of S.grahami in two lakes close to Fuxian Lake is discussed in relation to host speciation and coevolution of the host-parasite system. A new species of Proteocephalus from the fish Sinocyclocheilus grahami tingi, a subspecies endemic to Fuxian Lake in Southwest China, is described. This is the first report of cestode from this host. The new species differs from P. exiguus, P Longicollis, P parasiluri and P. torulosus, the only other species of Proteocephalus currently reported from China, by lacking an apical sucker from P. exiguus by having 45- 108 rather than 24-54 testes per proglottis, and a maximum of 15 rather than 28 uterine diverticula, from P. longicollis by having an average of 45- 108 rather than 75-115 testes per proglottis and testes being in a single layer instead of 2 layers; and from P. torulosus by having 45-108 instead of 150 testes per proglottis and testes being in 3-4 layers; and from P. parasiluri by having 45-108 rather than 180 testes per proglottis. It resernbles P. percae, P. pollanicola, and P. thymalli in number of testes and uterine diverticula, but with by lacking an apical sucker. Proteoc ephalus thymalli, like the new species, has a vagina that opens dorsally to the cirrus sac, but P thymalli slao has postovarian testes, which the new species lacks. The possible significance of parasitological examinations of the other two subspecies of S.grahami in two lakes close to Fuxian Lake is discussed in relation to host speciation and coevolution of the host-parasite system.