Phytoene desaturase (PDS) is the key enzyme in the biosynthesis pathway of carotenoids. In order to further explore the functions of PDS gene in Antirrhinum majus, the fulllength sequence and protein structure of AmPDS were analyzed, and the gene fragment of AmPDS was cloned. To investigate the expression profiles of AmPDS genes, the relative expression level of AmPDS gene in different periods and organs was detected by qRTPCR, the function of AmPDS gene was verified by VIGS, and the content of various pigments in leaves was determined by UV spectrophotometry. The results showed that： (1) the AmPDS gene forgment (500 bp) was cloned correctly, the cDNA of AmPDS gene was 1 743 bp in length, encoding 580 amino acids; Its protein molecular weight was 64.75 kD, and the the theoretical isoelectric point was 6.66. Homology analysis showed that the AmPDS gene has the highest sequence similarity to the sesame (Sesamum indicum). (2) qRTPCR analysis showed that the AmPDS gene was expressed in the whole plant, and the highest expression level was found in the upper lobes of the flower in fully opened period and leaves. (3) The pTRV₂AmPDS vector was successfully constructed and the VIGS system of snapdragon was established. The silencing efficiency of AmPDS gene was about 53% while the contents of various pigments in the leaves were significantly reduced comparing with the negative control. AmPDS is a key gene in the carotenoid biosynthesis pathway of snapdragon, and its obvious phenomenon can be used as an indicator gene for the VIGS system of snapdragon, which can lay a foundation for the further study of other gene functions of snapdragon.