Shenyang city is located in the intersect zone among Changbai, Mongolia and North China flora, which has a plenty of plant species belonging to 98 families, 371 genera and 779 species. There are 85 plant species in the largest family Companulaceae, and more than 20 species in the families Cyperaceae, Rosaceae, Leguminoseae, Polygonuceae, Labiatae, Lilaceae and Ranunculaceae. These families have 384 species in total, and 49.3% of them are found in Shenyang city. The flora had 23 geographical components types, and 89.3% of them were of the temperate type. Based on the epigenesis and functions of vegetation and the role of the dominant species, the urban vegetation in the downtown area of Shenyang was divided into 3 vegetation classes, 14 vegetation groups and 57 vegetation types, and the components, structure, dynamics and functions of 3 representative vegetation classes were analysised.