Abstract: The ecological and biological propagation characteristics of the alien plant species Plantago virginica were observed and surveyed from 2010 to 2012 to analyze its perniciousness in Kunming area. The study indicated that P. virginica turned into a perennial herb, the morphological characters of each organ changed greatly. Its flowering and fruiting phases were prolonged (flowering phase was from April to October, and the fruiting phase lasted from June to November), and the mean seed weight was also increased. Both the artificial experiments and field observation showed that its pollens and seeds could germinate normally, indicating that P. virginica had completely adapted to the warm and dry climate of winter season in Kunming through the integrated asexual and sexual reproduction. The survey showed that P. virginica mainly settled on both sides of the roads, in bare, abandoned land or on the wild grassy slopes. It often grew with other weed species, but it had not been found in the forests close to Kunming City. P. virginica grew vigorously on the campus of Southwest Forestry University, in Kunming Institute of Botany and in road side lawns. It was proposed that long term dynamic monitoring of its populations, and root eradication should be conducted at appropriate time to eliminate it.