Abstract:Paeonia lactiflora is a traditional Chinese flower. The traditional cultivars are diploid, and cultivating new cultivars has become an important goal in breeding. We selected three new cultivars of peony triploid, ‘Brightness‘, ‘Roseletter‘ and ‘Coral Sunset‘, and observed its meiosis behavior of pollen mother cells by fluorescence microscope. The pollen mother cells of the same variety with same bud diameter were not divided synchronously. But the majority performed same meiosis state. The different cultivars of the similar bud diameter were also different in the period of meiosis, and had significant differences. There were many chromosome abnormal behaviors in the meiosis of pollen mother cell of triploid cultivars, such as the univalent chromosome, the trivalent chromosome, the chromosome bridge and unequal separation and so on. These abnormal behavior leading to triploid pollen fertility is very low.