Abstract: Tamarindus indica L. is a tropical plant from genus Tamarindus L. in Leguminosae, whose fruit has high nutritional value and important medicinal value. The yield and quality of T. indica fruit are closely related to the development of the fruit. As a newly introduced species, there is little research on its reproductive biology process. To find the efficient measures to improve quality and increase yield of the fruit, conventional paraffin method and fluorescence microscopy were used to observe the mega-sporogenesis and microsporogenesis, as well as the development and fertilization of male and female gametes of T. indica. The main results were as follows: ① The anther of T. indica consisted of four pollen sacs, deformable tapetum, and mature pollen grain had 2-celled pollen, three germ furrows. The ovary was unilocular, bitegmic and crassinucellate. The type of embryo sac belonged to the Polygonum-type. The mature embryo sac synergid degenerated, while the antipodal cells degenerated in the early stage of development. ② The embryo sac developed normally, whereas, pollen exhibited the abortion phenomena of nuclear degradation, cytoplasmic concentration and cell shrinkage during its development. Meanwhile, there were some empty chambers in pollen sacs. ③ The artificially pollinated pollen could germinate normally on the stigma, and 6 hours later, the pollen tube extended to the ovary to complete fertilization. This study is helpful to reveal the reproductive biological process of T. indica, and would provide a reference to improve quality and increase production.