Abstract: 【Objective】The objective of this study was to analyze the physiological differences between the ISF line and the pistillate line of Ricinus communis L. and provide reference for the sex differentiation regulation of R. communis L. and its application in R. communis L. breeding.【Method】The chlorophyll relative content, net photosynthetic rate, soluble nutrients and endogenous hormones in leaves were analyzed at the bud stage and flowering stage by using the highly homozygous ISF line and pistillate line with the same genetic background as tested materials. 【Result】At the bud stage, the contents of soluble sugar and cytokinin of ISF line were significantly higher than those of pistillate line, with the increase of 36.9% and 61.5%, respectively and the gibberellin content of ISF line was significantly lower than that in pistillate line, with a decrease of 25.6%. At the flowering stage, the chlorophyll relative content, net photosynthetic rate, gibberellin, auxin and ethylene content in the ISF line were significantly higher than those in the pistillate line, with the increase by 15.2%, 23.3%, 13.8%, 33.5% and 73.8% respectively, while the contents of soluble sugar, soluble starch and abscisic acid significantly decreased by 38.0%, 54.9% and 14.8%, respectively.【Conclusion】The formation of ISF was characterized by the increase of soluble sugar and cytokinin, followed by the obvious increase of nutrient consumption, chlorophyll content, net photosynthetic rate, contents of gibberellin, auxin and ethylene, and the decrease of abscisic acid concentration.