Abstract: A parasite was isolated from Coilia nasus collected from Yangtze River.Morphological(light,scanning electron microscopes) and molecular(28S rRNA amplification)methods were used to identify the species of the isolates.Their typical characteristics:haptor not clearly distinguished from body proper,provided with 4 pairs of heteromorphic clamps.Two clamps on one side are larger than other six clamps.Narrow posterior appendage with 2 pairs of sharp hooks and egg with long filament.The results of sequence alignment showed 100% homology to 28s of Heteromazocraes hexacantha.Neighbor-joining methods of phylogenetic tree also showed that the isolates were in the same clade with H.hexacantha,These results suggested that this parasite is Heteromazocraes lingmueni, and its 28S rRNA was measured for the first time in this study.