There are many alluvial islands on the main stream of Heilongjiang, and the Sino-Russian borders mainly include: Gucheng Island, Opple Laojiji Island, Wubaliao Island, Yinjiada Island, Hedong Taozi Island, Zhongdiyingzi Island, Daheitong Island, Dahei Island, Huanghekou Island, Xiamachang Datong Island, Erdaoka Island, Kaniu Lake West Taozi Island, Kaniu Lake East Taozi Island, Hormuz Island and Wang Amu River.

Fuyuan Delta is also called "Black Box Island". Fuyuan Waterway is located in the triangle where Heilongjiang meets Wusuli River, with Fuyuan Waterway in the west and Russia across the river in the north and southeast, so it is called Fuyuan Delta, which is a closed island surrounded by water on three sides. Hejian island. The whole island includes Heixiazi Island, Yinlong Island, Mingshui Island, Xiaohe Island, Maple Island, Chrysanthemum Island, Dongjia Island, Qidao Island and Jiuliang Island, among which Heixiazi Island is the largest, so it is called "Heixiazi Island". Fuyuan Delta is about 58.85km long from east to west and about 14.0438+0km wide from north to south. The island covers an area of 350 square kilometers in dry season and 327 square kilometers in flood season, with an altitude of 39 meters.