Abstract: The culture solution of four different potassium(K) concentration were studied on grow of saffron(Crocus sativas L.) The result showed that K content and chlorophyll content, relative ATP content, net photosynthetic rate in leaves increased with improving K concentration, which enhanced the function of leaves to be metabolic source. On the other hand, the ability of the absorbing K, soluble sugars content, vitamin C(Vc) content as well as protein content in new-born corms were increased with increasing K concentration, which also strengthened the function of new-born corms to be metabolic sink. This article explored the mechanism that K could promote the new-born corms growth rate of saffron through strengthening the function of source and sink. These provide the new data for further study and utilization of saffron.