The study of gene function in Phalaenopsis aphrodite is hampered by the low efficiency of transformation systems and the long time span needed for the generation of transgenic plants. Therefore，the establishment of transient expression system of Phalaenopsis aphrodite petals will be an effective method for gene function analysis. An experiment was conducted to investigate the transient expression mediated by Agrobacterium tumefaciens using the sepals and petals of Phalaenopsis aphrodite （P. ‘Big chili’）. Effects of A. tumefaciens concentration，infection time，acetosyringone concentration，and coculture length on the transient expression of βglucuronidase（GUS）gene were analyzed to determine the optimal transformation condition. The chalcone synthetase gene RNAi interference vector was transiently transformed into the petals of Phalaenopsis aphrodite. After 3 days of cocultivation, changes in the phenotype and pigmentation of the flower color were observed，and RTPCR was used to detect the expression level of CHS gene transcription. （1）A higher transient expression level of GUS gene could be obtained as OD₆₀₀ value of A. tumefaciens 0.6，infiltrating for 60 seconds，adding 150 μmol/L acetosyringone to coculture medium，and coculture for 3 days in darkness. It reaches 85.01%. （2）The color of the petals of transgenic Phalaenopsis aphrodite was significantly lighter and pigment content decreased. （3）Semiquantitative PCR showed that the transcriptional activity of CHS gene was significantly lower than that of the control group. The experiment successfully established a rapid gene function verification method，providing technical support for the study of gene function and breeding work of the Phalaenopsis aphrodite.