Abstract: The total length cDNA of Leafy (LFY) was cloned and sequenced from wild type Arabidopsis thaliana (L.) Heynh. The plant expression vector with CaMV 35S promoter for LFY cDNA was constructed and transformed into Chrysanthemum morifolium (Ramat.) Tzvel. The result proved that the LFY eDNA contained 1 263 base pairs in total length, encoding 420 amino acid. After Southern and Northern blot analyses the plants were grown in flowerpot, eight transgenic Ch. morifolium, plants were obtained. Compared with the normal plants, three of them flowered 65,67 and 70 days earlier and two of them delayed flowering 78 and 90 days, respectively.