Abstract:Abstract: In order to know the ability of keeping polyploidy of artificial induction and the growth habits of Paulownia tomentosa(Thunb.)Steud. after being stumped,the polidy, the sprout number, growth rate, leaf characteristics, chlorophyll contents, and photosynthesis characteristics of stumped regeneration five-year old tetraploid and diploid Paulownia tomentosa(Thunb.)Steud.were studied by authors. The results showed that the stumped regeneration tetraploid Paulownia tomentosa(Thunb.)Steud. can steadily keep the polyploidy ploidy.The differences between tetraploid and diploid Paulownia tomentosa(Thunb.)Steud.were found as follows① lesser sprout number and slower growth rate in tetraploid. ②The mean length of the stomata was longer in tetraploid plants than diploid plants, and stomatal frequency was reduced with the increased ploidy level. ③Chlorophyll content in leaves reduced but photosynthetic rate increased in tetraploid.④The tetraploid and diploid plant differed significantly in leaf shape, with those of the former being round with serrate margin and those of the latter pentagonal with entire margin. In addition, few chimeras demonstrated the superiority of inducing polyploid by tissue culture. The characters of shorter internodes, thicker leaves and bigger flowers of polyploid Paulownia tomentosa(Thunb.)Steud.were very propitious to breeding garden plants, include arbor and flowers.