Abstract: Bambusa multiplex is a beautiful ornamental bamboo species. It has been flowering in recent years. In order to understand the development process of flower bud differentiation and male gametophyte, the experiment was done by the methods of the paraffin section and scanning electron microscopy. The results are as follows, the developmental order of a flower is lemma, palea, lodicule, stamens and pistil. Stamens 6, the developmental sequence of the anther primordium is the primordium near the rachilla, four primorolium at the both sides and the primodium away from the rachilla. The anther wall is monocotyledonous type and the tapetum is glandular type. The cytokinensis is successive and the microspore tetrads are bilaterally. Mature pollen grains are 3-cell with one germination aperture.