To systematically reveal the change of organs of Oplegnathus punctatus at its early stage of digestive system development,continuous histological sections of O.punctatus aged from 1 to 49 days were analyzed.The results showed that the digestive tract of 1-day-old O.punctatus was located inside the yolk sac and was only a simple tubular structure.The development of the digestive system of O.punctatus can be roughly divided into three stages.At 1~3 days of age,the digestive system was still in the primitive stage.At this age,the mouth fissure was closed,and only the yolk sac was used as the nutrient source,thus presented a complete endogenous nutrition.At 4~20 days of age,the digestive system was preliminarily developed,and it was in the transition stage with basic feeding,digestion and absorption capacity.At this stage,the mouth fissure opened,the yolk sac gradually disappeared,and the hepatopancreas developed rapidly.The fish gradually developed the ability to digest food.The tran-sition to exogenous nutrition began.Tt 21 to 35 days of age,the digestive system developed further and the gastric glands appeared,forming a complete digestive system.After that,the tissues and organs of the digestive system only increased in cell scale rather than structural changes.