The studies on feeding ecology of fish are the basis for understanding the function of the whole community and ecosystem,and they will also contribute to the fisheries management.DNA barcoding is a new way to study the stomach contents,and it will also improve accuracy of the results on dietary composition by combining with morphological analysis.Hexagrammos otakii is an important commercial fish and possesses potential in aquaculture industry.Stomach contents analysis of H.otakii was investigated based on 482 individuals collected monthly from the shore reef of Lidao Rongcheng between March 2010 and February 2011.The main results were as follows:H.otakii was the demersal-feeding fish.Among the 10 prey groups,fish was the dominant prey group,and they also included polychaeta,decapoda,algae,crabs and stomatopoda,etc.The dietary composition had obvious seasonal variations:decapoda was the important prey group in every season,crabs and polychaeta in spring,fish in summer and autumn,and polychaeta were mostly in winter.The dietary composition also had obvious ontogenetic variations:<80 mm SL preyed on decapoda and amphipoda;80-119 mm SL preyed on polychaeta,stomatopoda larvae and decapoda;>119 mm SL preyed on fish,decapoda and crabs.The feeding intensity had obvious seasonal variations,with highest in summer and lowest in winter.The feeding intensity also had obvious ontogenetic variations,reached the highest feeding intensity in <80 mm SL,then decreased with increasing standard length,and gradually increased after >180 mm SL.Six samples could be identified based on DNA barcoding,among which,four samples were identified as species,other two samples were identified as genus and family respectively.