【Objective】The flower morphological structure and anther abortion of Phyllostachys nigra are analyzed to explore the reasons for its low seed-set rate.【Method】The flower organs, mega- and microsporogenesis, as well as the development of male and female gametophytes, are observed through morphological examinations of the spikelets and paraffin sections using flower samples of P. nigra from the bamboo garden at the Southwest Forestry University. 【Result】The P. nigra inflorescence is a limited inflorescence, with the florets at the top blooming first, followed by the florets at the bottom. The spikelets cluster at the nodes of floral branches, with latent buds located at the base of the spikelets. The Ph. nigra florets are open, containing one palea, one lemma, three stamens, three lodicules, and one pistil. The lodicules are membranous and transparent, with well-developed cilia along the edges. The anther of P. nigra is approximately 8 mm long, containing four symmetrical sporangia. At the sporogenous cell stage, the anther wall consists of four layers: epidermis, endothecium, middle layer, and tapetum, from the outside to the inside. After anther maturation, two-celled or three-celled pollen grains are produced, and the anther wall comprises only two layers. The ovary is unilocular with parietal placentation, containing an anatropous ovule and three-lobed, feathery stigmata. 【Conclusion】Multiple abortions occur during the development of the stamens, which can be the key reason for the low seed-set rate of P. nigra.