AbstractAn overview of research progress of urbanization impacts on plant biodiversity was given. With a worldwide expanding of urbanization, especially in developing countries, effects of urbanization on biodiversity are attracting more attention. Urbanization reduces native plant species whilst increases introduced plant species. As for distribution of plant species, richness of native plant decreases along rural, rural-urban fringe and urban gradient. However, richness of introduced plant species increases, which results in increasing of total plant species richness along the same gradient. Urbanization also produces the great influence on plant species composition and makes the dominant species varying along the gradient. The mechanism of urbani-zation affecting plant biodiversity mainly lies on three aspects, i.e., introduction of exotic species, change of microhabitat, and altering of landscape pattern. Concerning further researches, four main trends will become more and more important: (1) systematical integration of different regions, various methods and multi-disciplines, (2) long-term site monitoring the urban expanding and plant biodiversity changing, (3) re-search on interior mechanism of native plant species’ loss and characteristics’ change, especially the in-ter-actions between the exotic and native plant species, and (4) urban plant biodiversity conservation.