Only a few of the world's 275 species of Sciaenidae live in fresh water throughout their life; one of which, is the freshwater drum that is wildly distributed in North American. The study of its morphological and internal anatomical characters have great value to the phylogeny and evolution of Sciaenidae. In present study, the external morphological characters of the juvenile freshwater drum were systematically measured, and the anatomical structure of the main internal organs and sagittae otoliths were observed. The results indicated that there were two kinds of scales covering the body of the freshwater drum, except for the front of the snout, chin, and isthmus. Small cycloid scales were found on its operculum and around the eyes on both sides of the head, and ctenoid scales covered the body including the posterior head and jugular. The lateral line scales extended from the back of the head to half of the caudal fin. Some transition types of cycloid and ctenoid scales existed at the junction of the head and the dorsum. The first membrane of the ventral fin extended slightly to form a specific fin-silk. The juvenile freshwater drum had canine-like jaw teeth and pharyngeal teeth with different sizes, but all bent in an inward internal direction of the pharyngo-oral cavity. The upper pharyngeal disc was divided into two symmetrical parts, whereas the lower pharyngeal disc was fused into one. There were only five mental pores symmetrically distributed on the chin, which were Sciaena-form. The digestive tract consisted mainly of the pharyngo-oral cavity, a short esophagus, a divination-type stomach, the intestine with two bend, and the anus. There were seven circular digital pyloric caecas existing at the junction of the stomach and the intestine. The morphological characteristics of the sagittal otoliths of freshwater drum were similar to those of . Based on the external morphology and internal anatomical characteristics, the freshwater drum has a closer evolutionary relationship with the Sciaena and should belong to low-grade benthic carnivorous fish, which consisted with its specific ecological habits and food consumption characteristics. This study not only provided an important foundation for the artificial domestication of freshwater drum and the large-scale parasitic breeding of pink heelsplitters in China, but also provided the basic material for the study of the evolution of the geographical evolution pattern of Sciaenidae in marine and freshwater regions.