Abstract: The biological characters of wild Buddleja davidii populations were investigated in vicinal region of Sichuan and Yunnan provinces.The result suggested the average branch,numbers of individual,the average diameter of the biggest stem of individual in population and the average height of population showed distinct pertinence as altitude change.However,the average inflorescence(infructescence)length of population and the average quality of 1000 seeds showed little pertinence as altitude change.Furthermore,germination percentage of B.davidii enhanced as deposited time increase in four years.Light has a minor effect on germination percentage.Finally,the reason why B.davidii can become an invasive species in some other countries and may not endanger native biodiversity was discussed according to the present results.