Abstract: 【OBJECTIVE】In order to find out a new pathway for utilizing heterosis of Zinnia elegans and accelerate breeding process, the mechanism of anther development of a male sterile line was explored. 【METHOD】 Backcross, Sibmating, Selfing of fertile plants and testcross with inbred lines were analysed and identified in the field, and cytomorphology was observed.【RESULTS】Recessive nucleus male sterile line AH209AB that capable of working as a maintainer was obtained by successive backcrosses with male sterile plants and fertile F1 plants as male parents. Cytological and anatomical studies indicated that: (1) The wall of normal anther was constituted of four layers of cells such as epidermis, powder chamber wall, middle level and tapetum cells. The process in meiosis of pollen mother cell in Zinnia elegans was normal, cytoplasm divided simultaneity. Mature pollen grains were tricellular. (2) The petal of male sterile plant degenerated as a threadlike structure, the stamen were villiform in appearance and no pollens were formed. The result showed that the growth of anther of male sterile plant is inhibited at the stage of chear sporial cel1 or the stage of sporial mother cell. During bud development, the size of the aborted anther was increasing but did not differentiate the sporogenous cell and the pollen sac. There was no evident boundary between tapetum cell，middle lamella and inner wall of PMC. Tapetal cells did not develop from the very beginning. So the abortion type was completely structural male sterility. 【CONCLUSION】 The male sterile line belongs to non-sporange male sterile type and is of great use in F1 seeds production.