The Okinawa Trough (OT) is a new moon-like back-arc rifting basin, in tense tectonic activity and drastic magmatism are main characteristics for it and adjacent areas. In this paper, according to major, trace elements, Sr-Nd isotopic and age data of volcanic rocks, volcanic properties and distribution as w ell as their link with geological background and evolution were discussed in order to understand the development of magmatism and tectonics on the OT and adjacent areas, deeply. The main conclusions are as follow: (1) Geochemic data show that volcanic rocks from the basin-arc system belong to cal-alkali rock groups, including basalts, basaltic andesites, and rhyolites. The magmatism is bimodal. (2) Rock compositions are different in different parts of the study area. Depth variation of magma source can be though t as a major factor to lead these differences. In middle and northern study area, volcanic rocks are mostly andesites and ryolites. The former mainly located in middle and northern trough, and was juvenile rocks (<1Ma); The latter outcropped in the arc and formed during Miocene. Volcanic rocks in southern study area mostly contain basalts and basaltic andesites. From old to young, they located at Ryukyu arc (RA , 6～18Ma), Northern Taiwan Volcanic Zone(NTVZ, from 3M a-present), and central grabens (Quaternary). (3) Ryukyu volcanic arc (including the southern arc) have been formed since middle and late Miocene (8～6M a). The continental extension behind RA caused the Northern and middle OT opening about 6M a ago, but the collision between Luson Arc and Eurasian plate changed geodynamical conditions in this region about 12Ma ago and led that southern OT opening was later than middle and northern OT. This kinetic change hasn't affected on middle and northern OT, because Keram a Gap stopped the effect of the event. In addition, southern OT should belong to the back-arc basin, because southern RA has been formed about 13Ma ago.