The South China Sea, located in the south of Chinese mainland, is one of the three marginal seas of the western Pacific Ocean and China. The natural sea area of this sea area is about 3.5 million square kilometers, which is the largest and deepest sea area in China's offshore area, with an average depth of 12 12 meters and a maximum depth of 5559 meters.
The South China Sea is about 2000 kilometers long from north to south and 1000 kilometers wide from east to west. It starts from the connecting line between Nan 'ao Island and the southern tip of Taiwan Province Island in the north, reaches kalimantan island and Sumatra Island in the south, Chinese mainland, Indo-China Peninsula and Malay Peninsula in the west, and reaches the Philippines in the east, and is connected with the East Pacific Ocean and the West Indian Ocean through straits or waterways. It is a semi-closed sea with northeast-southwest trend.