Male sterile mutant was observed in Taraxacum junpeianum Kitam. To study the property and genes, we investigated anther development and pollen mother cell meiosis of male sterile mutant and normal wild-type of Taraxacum junpeianum Kitam. through morphology, paraffin section and chromosome technique. The results showed that the middle part of anther of male sterile mutant was red and withered without pollens. Compared with normal wild-type, male sterile mutant had shorter stamens, narrower ovaries, longer and narrower seeds. Abortion stage arose during tetrad to early mononuclear microspore, induced unusual decomposition of tapetum, and mutual adhesion of microspores. Lagged micronucleus was observed during dyad phase of microsporocyte meiosis in male sterile mutant, few tetrads of abounding chromosome bridges were emerged, loss of nutrients happened, leading to abortion of microspore eventually. The male sterility in the dandelion mutant was stable and thorough. Unusual decomposition of tapetum may result in male sterile of dandelion.