On the east coast of Eurasia and the southern tip of Liaodong peninsular in northeast China, Dalian stretches from 120.58' to 123.31' east longitude and 38.43' to 40.10' north latitude, with the Yellow Sea on the east, Bohai Sea on the west, facing the Shandong peninsular across the sea on the south and backed up by the vast Northeast Plain on the north. Dalian is the marine gateway of northeast China, North China，and East China. It is an important port, and also serves as a centre for trade and tourism.

Dalian covers an area of 12,574 square kilometers, among which 2415 square kilometers of area is its old city. This area is abundant with mountains and hills, while plains and lowlands are rarely seen. The terrain, high and broad on the north, low and narrow on the south, tilts to the Yellow Sea on the southeast and the Bohai Sea on the northwest from the center. The region which faces the Yellow Sea is long and gentle. The Qianshan Mountain range of Chang Baishan Mountain system passes through the whole region from north to south. Mountain regions and long eroded foothills are widely scattered within the region. Plains and lowlands are only interspersed near the confluence and in some valleys. Karst topography and sea erosion topography are everywhere.

Dalian is in the warm-temperate zone, with a continental monsoon climate and oceanic features. The four seasons are quite mild, with neither a severely cold winter, nor an extremely hot summer.