The rock bream, Oplegnathus fasciatus, a subtropical and carnivorous species, is an economically important marine fish in East Asia. The high commercial and ornamental value makes it a promising aquaculture species in the future. However, to some extent, the lack of information on ontogenetic development has restricted the breeding industry of this species. In this study, the allometric growth in rock bream was analyzed. The results are as follows: at the general condition for fingerling-production, the total length and body weight of rock bream larvae were measured from hatching to 50 days post hatching. The increase of total length and body weight could be estimated with the Cubic function and took on the S-Curve. The curve could be divided into three phases and each phase possessed different growth rate. The head length, head height, trunk height, eye diameter, mouth width, rostrum length, abdomen length, and tail fin length of rock bream were measured and the relationship between them and the total length was analyzed. The result showed the allometric growth in rock bream larvae. By analyzing the inflexion points in growth curves, in combination with morphological development of the larvae, we found that some important organs (head, mouth, eye, digestive tract and fins) had developed prior to other ones. In rearing rock bream larvae, the best environmental condition should be established by making the important organs prior development.