East Asia, Northwest Pacific China is located in the southeast of the Eurasian continent (East Asia) and the west coast of the Pacific Ocean, with a land boundary of more than 22,800 kilometers, and is adjacent to 15 countries. East of Korea; South of Vietnam, Laos, Myanmar; Southwest borders India, Bhutan, Sikkim, Nepal, Pakistan and Afghanistan; The northeast is adjacent to Russia; It borders Tajikistan, Kyrgyzstan and Kazakhstan in the northwest; It borders Mongolia in the north. The coastline of the mainland is about 18000 km long, starting from the Yalu River estuary at the junction of China and North Korea in the north and reaching the Beilun River estuary at the junction of China and Vietnam in the south. Maritime neighbors include Japan in the east and the Philippines, Indonesia, Brunei, Malaysia and Singapore in the southeast. Latitude and longitude position: the northernmost part of the territory is on the central line of the main channel of Heilongjiang in the north of Mohe River (53 31'north latitude), the southernmost part is in Zengmu shoal in Nansha Islands (near 4 south latitude), the easternmost part is at the junction of the main channels of Heilongjiang River and Wusuli River (east longitude135 5 5'), and the westernmost part is on the Pamir Plateau west of Wuqia County, Xinjiang Uygur Autonomous Region (1).