Developing and transitional countries undergoing rapid economic development will face growing problems with biological invasions because international commerce will bring new invaders. We assessed the potential for plant invasions in China by comparing the country's current invasive flora with that of the United States, a nation of similar size and latitudinal span but with a different history of plant introductions. Invasive plant species richness in the United States is about twice as high as it is in China. The remarkably lower fraction of invasive woody plants in China suggests that more alien trees and shrubs could invade Chinese habitats. Road density correlated with invasive plant species density among geographical units, with numbers for China lower than those for the United States. The data suggest that China has been invaded less than the United States has, and that the potential for new plant invasions in China is high. Measures toward preventing biological invasions are needed and timely—steps taken now can prevent adverse impacts from future invasions.