The present paper deals with the larvae of tuna-like fishes collected aroundwaters of Xisha Qundao of the Nan Hai, during the period in January 1975 to May1976. The larvae and postlarvae of the tunas, tuna-like fishes, were described. Theybelong to Scombridae (Grammatocynus bicarinatus), Thunnidae (Katsuwonus pelamis,Euthynnus yaito, Auxis thazard, Thunnus thynnus, Thunnus albacares, and Thunnusobesous). The morphology of these tunas larvae were described as will as the ecology andspawning seasons. There is a close resemblance at same body length between larvae of Katsuwonusoelamis and Thunnus thynnus, in the distribution of chromatophores on the ventrallobe of the tail. The head of the former is large and long (about 30-40% of the bodylengthes) but of the latter is small and short (about 29.33-32.93%). They also differfrom each other in the following features.