The influence of the growth of Platycodon grandiflorum and its active constituent by spray zinc of different concentration had been studied by a pot experiment in a weather enclosure The result showed that spraying zinc could increase the content of chlorophyll and carotenoid of leaves，enhance photosynthesis，promote the growth of root，and improve the content of total saponins and total polysaccharides in the root of Platycodon grandiflorum And the content of chlorophyll a and carotenoid,photosynthesis，the diameter，weight and the content of total saponins of root showed up increased at first，then decreased as increasing of zinc concentration While plant height and total polysaccharides do not showed any rule And spraying zinc did not have significant difference on chlorophyll b and the length of root The conclusion was that 600 mg/L was the optimal concentration to spray zinc on Platycodon grandiflorum