One year old seedling of Cinnamomum longepaniculatum,Michelia platypetala,Michelia foveolata and Manglietia chingii were selected for this experiment.The purpose of this paper is to study the change of cell membrance permeabilities of four species on the Pb stress in the soil.The results have shown that the cell membrance permeabilities of all of tree species in this experiment increased under the stress of different Pb concentrations and they respresented different grades of harmfulness.On basis of variance analysis and multiple-factor comparison(SPSS 11.5),the tolerance of four species to Pb stress could be preliminarily ordered as:Cinnamomum longepaniculatum,Michelia platypetala,Micheia foveolata,Manglietia chingii.