In order to understand the species composition and distribution of tuna larvae assemblages in relation to hydrograhic conditions in the surrounding waters of Taiwan, five sampling cruises was carried out at 62 stations around waters of Taiwan in 2005, 2007 and 2009. A total of 131 larval tuna were collected, including 28 T. alalunga, 48 T. albacares, 28 T. obesus and 27 T. thynnus. A large proportion of the larvae were at preflexion and flexion stage. In spring, the ambient sea surface temperature for T. alalunga, T. albacares, T. obesus and T. thynnus were 27.12、27.06、27.15 and 27.54℃, respectively. In summer, the ambient temperature for T. alalunga, T. albacares, T. obesus and T. thynnus were 30.26、30.07、29.89 and 30.20℃, respectively. The result indicated that larval tuna were mainly distributed in the Kuroshio current and southern Taiwan Strait, and were more abundant in oceanic area than in coastal area. However, the distribution patterns varied annually, which might be associated with the fluctuation of the path of Kuroshio current. Moreover, abundant larval tuna have been observed during spring and summer, and little was observed after the peak spawning season in summer. In conclusion, parts of the spawning grounds of the highly migratory tuna probably locates in the EEZ of Taiwan. Further studies are required for a better fisheries management, protection of spawning grounds and obligation for responsible fishery.