Abstract: Bishanopliosaurus youngi Dong, 1980 from the Jurassic Dongyuemiao Member of the Ziliujing Formation in Chongqing Municipality, China is redescribed in detail. The holotype of B. youngi is the postcranial skeleton of a young individual, but so far the most complete plesiosaurian fossil known from the Asian Jurassic. Our restudy indicates that B. youngi can be diagnosed by the bifurcated sacral ribs combined with the compressed neural spine, narrow coracoid, and the humerus with a peculiar projection. B. youngi is a valid taxon, but its phylogenetic relationships with other plesiosaurians remain uncertain mainly because of the lack of cranial features. Previous studies on the Dongyuemiao fauna and flora indicate that the sediments are of subtropical freshwater origin. The discovery of B. youngi added further information on the freshwater invasion of plesiosaurians. Freshwater plesiosaurians so far known are very fragmentary, but their wide geographic and temporal distributions suggest that the presence of plesiosaurians in freshwater environment was not uncommon in most of their history.