Changes of external morphology and physiological indexes of one year old seedlings of Sapium sebiferum from different provenances under continuous drought were studied.The results showed that:(1)The growth of S.sebiferum seedlings was negatively influenced by different degree of drought stress,and external morphology characteristics of water shortage were distinct.Relative water content of leaves decreased under drought stress,but that raised again after rewatering;(2)Under extreme drought stress (at the 12th day),net photosynthetic rate of seedlings maintained certain intensity,and the change of relative membrane permeability was not obvious,so resistance of S.sebiferum seedlings to drought stress was stronger;Among drought period both SOD and POD activities enhanced,contents of soluble sugar and soluble protein increased,MDA content climbed,proline accumulated,and the change reversed after rewatering,so seedlings could maintain normal osmotic adjustment ability to drought;(3)At the same time experiment showed that changes of physiological indexes except for MDA and relative conductivity rate of S.sebiferum seedlings from different provenances were significantly different (P<0.05),some was very significantly different (P<0.01).Under extreme drought stress,there were stable genetic variations among them;(4)Through comprehensive analysis of Fuzzy,it was concluded that the tolerating ability to drought of both Huangshan Anhui and Shangcheng Henan provenance were the strongest among 5 provenances,as their synthetic evaluation index were the biggest comparatively,and their cultivation and applying in seasonal arid region should be extended.