Fourteen individual yellow fin tuna (41-75.5cm fork length) , were tagged with ultrasonic telemetry tags and released around a subsurface FADs in the coastal waters Che-Cheng , during July to October 2008 . We set an acoustical receiver at 40 meters underwater on the FADs （22。07.20'N；120。24.20'E）, and the second one was 600 meters apart from the first receiver in the southeast direction. Other the FADs(22。11.215 'N; 120。 19.235 ' E) , we tracking with VR28 receiver on the ship. The maximum associating period of 14 days was observed on a 60cm yellowfin tuna. In vertical distribution, the fish mostly stayed in the depth of 40-60 meters in daytime and dived to the maximum depth of 160 meters. In nighttime, the larger size of fish gathered in the depth of 20-60 meters and the smaller sizes mainly gather in the shallower waters of less than 20 meters deep and occasionally to 200 meters deep.