| Okinawa Trough is a new back-arc basin developed in the continental margin. To the east is Ryukyu arc-trench system, which is an active subduction zone. Beneath the Ryukyu trench, Benioff zone dipping NW shows Philippine Sea Plate is subducting under the Ryukyu Trench. To the north is Kyushu. Taiwan-Luzon arc, which is an arc-continental collision zone, is the south extremity. Researches suggest that the evolutions of the different parts of Okinawa Trough are not similar, especially between the south part and the north, middle part, not only in the opening time but also in the forming mechanism.In this paper, the seismic sequences and structural characteristics in the southern Okinawa Trough were analyzed and discussed. And the evolution was restored by 2DMove software. According to all of the results, we can concluded that,1) the seismic sequences developed in the west shelf, trough basin and Ryukyu Island arc are different.West shelf. Sequences I is Quaternary shallow sea alternate clay and silt. There are grayer grit interbedded by biologic debris in the bottom. Sequence IV is Pliocene sea-onshore transition grayer, grayish gritstone, siltstone and mudstone and becomes thicker sea facies toward trough. Sequence V is Miocene swamp variegated silt, mudstone interbedded by coaly shale and coal seam. The Oligocene middle grain silt probably deposited in the bottom. Sequence VI is Eocene shallow sea and offshore grayish silt interbedded by biologic limestone and mudstone. In the bottom exists grit. Sequence VII is Paleocene shallow sea and offshore charcoal grey mudstone and calcific sandstone.Trough basin. Sequence I can be distinguished from the northwest slope to trough basin and is Holocene softy sediments. Sequence II only distributes in the trough basin. We inferred that it is middle-late Pleistocene abyssal ooze and turbidity. Sequence III that is early Pleistocene sediments also only distributes in the trough basin. We found that sequence IV, which is Pliocene sediments, only exists in the slope and island arc slope and not distributes in the trough basin. In some areas of the trough basin, sequence V, which is residual Miocene sediments, deposited beneath the sequence III. Paleogene and Mesozoic or older strata make up of the acoustic basement.Ryukyu Island Arc. Sequence I is Holocene softy sediment. Sequence IV-2 is upper Shimajiri group, which is made up of siltstone and mudstone. In its lower part sandstone and tuff interbedded. Sequence IV-1 is lower Shimajiri group, which is made up of sandstone and the lower mudstone and siltstone. Sequence V-2 is upper Yaeyama group. Light grey – light red grey finest – fine sandstone and a little coaly sandstone and interbedded mudstone make up of this sequence. There is also pitch coal and lignite in this sequence. Sequence V-1 is lower Yaeyama group. Limestone is near the upper interface. Finest – middle grain quartz sandstone and back shale, which includes calcific agglomerate and shell debris, make up of this sequence. Because of the profile poor quality under this sequence, the other reflections cannot be distinguished easily.2) There are three basic morphologic parts, namely west slope, trough basin and Ryukyu Island Arc slope. The topography of the seafloor is very complex and there are some kinds of morphology. But as a whole, it can be viewed as different parts along the E-W direction. The seismic profile show that the structures mainly include faults, submarine canyon, slides and slumps, submarine ridge, diapirs and rift valley.3) Applying 2DMove software, two seismic profiles were restored. The restoration and subsidence show that the initial active center lied in the west slope and then transferred to east and south via trough center during the evolution procession.4) According to our seismic interpretation, one evolution model can be constructed. In turn the procession is depositing, uplift and erosion and rifting, initial extension. Although Pliocene is absent in the trough basin, it developed in the past, so we take the Pliocene...
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