Abstract: Studies of otolith are the basic of research on growth and early life history of fishes. The present status on the methods of studying otolith morpha and its application on species discrimination are expatiated in this paper, as well as back-calculations on age determination, early development research, spawning period, hatchery phase, spawning area and special circumstance in early stage by otolith microstructure. The existent problems on research of otolith are discussed and proposals are suggested.