Abstract: The effects of the ethylene inhibitor 1-methylcyclopropene (1-MCP) treatment on the ACC oxidase activity during the flower blooming of Narcissus tazetta were studied by using the 3-year-old Narcissus tazetta seedballs of the polyanthus Jinzhan Yintai as the test materials, in order to provide theoretical basis for the study of the florescence regulation of Narcissus tazetta. In this experiment, three treatments were set up. Treatment 1 (treated with 1-MCP):when the heading height of Narcissus tazetta was 6-7 cm, 1-MCP was used to wrap the stem of Narcissus tazetta; Treatment 2 (treated with ethylene+1-MCP):After the seedballs were fumigated with ethylene for 15 days before planting, 1-MCP was used to wrap the stem of Narcissus tazetta when the heading height of Narcissus tazetta was 6-7 cm; Treatment 3 (CK):Narcissus tazetta was directly planted without any treatment. The activity of ACC oxidase in different flowering stages and different organs of Narcissus tazetta with different treatments was determined by using the enzyme-linked immunosorbent assay in the florescence. The results showed that the activity of ACC oxidase in Narcissus tazetta treated with 1-MCP showed a downward trend from the inflorescence stage to the early flowering stage, increased slightly from the early flowering stage to the full flowering stage, and then decreased, but it was relatively stable. And there was no significant difference in the activity of ACC oxidase among the early flowering stage, full flowering stage and the stage of senescence. Compared with that of 1-MCP treatment, the ACC oxidase activity of Narcissus tazetta treated with ethylene+1-MCP was always at a relatively high level, and showed a significant upward trend from the full flowering stage to the stage of senescence and maintained at a high level.The ACC oxidase activity of Narcissus tazetta treated with CK increased significantly from the inflorescence stage to the early flowering stage, while there was no significant change in the latter three stages, but it was higher than that treated with 1-MCP or that treated with ethylene+1-MCP. The activity of ACC oxidase in the whole flower of, ovule part Narcissus tazetta was significantly increased when treated with 1-MCP after the fumigation of ethylene at the stage of senescence, and the activity of ACC oxidase in the petals of Narcissus tazetta treated with 1-MCP or treated with ethylene+1-MCP was increased.