Fourteen individual yellow fin tuna (41-75.5cm fork length) , and four skipjack tuna were tagged with ultrasonic telemetry tags and released around a subsurface FADs in the coastal waters off Che-Cheng . We set an acoustical receiver（VR2W）at 40 meters underwater on the subsurface 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, we tracked the tagging fish with VR28 receiver on the ship. The maximum associating period of 31 days was observed on a 49cm yellowfin tuna. In vertical distribution, the fish mostly stayed in the depth of 60-80 meters in daytime and dived to the maximum depth of 250 meters. In nighttime, the fish gathered in the depth of 20-60 meters. Skipjack tuna stay around the subsurface FAD about few hours, and mostly stayed in the 20-120 meters deep. Gathered in the shallower waters of less than 20 meters deep and occasionally to 200 meters deep. The comparison of vertical migration during new moon and full moon; the vertical migration depth was 120 meters in daytime and nighttime during full moon, and the average depth was 46.3 meters. No significant variation of vertical migration was observed between daytime and nighttime during new moon, the vertical migration depth was 250 meters; the average habitat depth was 71.6 meters.