In order to explore the regulatory role of phytochromeinteracting factors(PIFs)in light induced floral scent synthesis and release, we cloned the coding region sequence from Antirrhinum majus‘Maryland True Pink’, bioinformatic analysis AmPIF4 were performed, and the subcellular location transient expression vector was used to transform tobacco and study the distribution of AmPIF4 protein in the cells in this study, and the temporal expression of AmPIF4 gene was detected by qRTPCR. The function of AmPIF4 was verified via virusinduced gene silencing (VIGS), and the content of floral scent component was determined by ATDGC/MS. The results showed that: (1) the ORF (open reading frame) of AmPIF4 gene was successfully cloned. It had a fulllength of 1 497bp, encoded 498 amino acids, and the theoretical isoelectric point and molecular weight of the encoding protein was 6.44 and 55.58 kD, respectively. Homology analysis showed that AmPIF4 protein had the highest sequence similarity to Sesamum indicum. (2) Subcellular localization assay showed that AmPIF4 protein was specially expressed in the nucleus. (3) qRTPCR analysis showed that AmPIF4 gene was expressed in the whole development period and different organs, and reached the highest level in fullyopened period, among them, the highest expression level was found in the leaves of the fullyopened period, but the difference of the relative expression in the leaves, stems and sepals was not significant. (4) The silence of AmPIF4 gene significantly reduced the relative expression of AmPIF4 gene by about 65% compared with wildtype in snapdragon petals, it was also remarkably reduced compared with the negative control. At the same time, the main floral volatile components in snapdragon petals, myrcene, ocimene, and methyl benzoate, were significantly increased by 22%, 24%, and 12% respectively compared with the wild type, the overall content of floral releases increased. This study suggests that AmPIF4 plays as a negative regulator in floral scent synthesis and release, and may participate in the regulation of light induced floral fragrance biosynthesis.