Abstract: The megasporogenesis and the development of female gametophytes of Nicotianarepanda W.and Nicotiana stocktonii B.were studied by applying paraffin section and morphological observation.The results showed that they were similar in morphology,they were self-pollination,tubiform floret,capsule.In embryology,they had bilocular ovaries,anatropous and multiple ovules,and after meiosis straight line tetrad was formed from megasporocytes,three of them degenerated,leaving only one as a functional megaspore to develope in embryo sac which had seven cells and eight nuclei.Difference was also shown both morphologically and embryologically between N.repanda and N.stocktonii as in plant heights,flower colors and sizes;they were also different in the time of forming buds ,flowering time,degenerating time of tapetum and the shape of cells in the sac.The phenomenon of abnormalities and abortion of embryo sac were not found.