Qiongdongnan Basin is located in the southeast of Hainan Island, and its geographical coordinates are east longitude 108 to12, north latitude 16 05' to north latitude 19. The basin is located in the southeast of Hainan Island, near the Xisha Islands. The Yinggehai Basin is bordered by the 1 fault in the west, the Shenhutan uplift in the east and the Zhu San sag in the south. The total area of Qiongdongnan basin is about 34,000 square kilometers, and the maximum sedimentary thickness exceeds 12 kilometers.