Meiosis behaviors of pollen mother cells and development process of male gametes were observed by carbol fuchsin stainin and paraffin sectioning method for exploring the cytological mechanisms on pollen abortion of Taraxacum coreanum Nakai.. The results showed that there were much many abnormal cases in the process of meiosis, such as lagging chromosomes, chromosome bridges, fragments, unsynchronized segregation and uneven division. Many micronucleus, dyads, triads, tetrads and polyads come into being during tetrad phase induced by the abnormal behaviors of chromosomes. Mature pollen of T. coreanum mainly belongs to three-cell type and partially hybridizes with abnormal generative cells. In general, abnormal meiosis in the process of pollen mother cell and abnormal development of generative nucleus of male gametes were the main reasons for the pollen abortion of T. coreanum.