The Phalaenopsis flower is special and highly evolved with three petal-like sepals,a labellum or lip(highly modified petal),a gynostemium or column (fusion of the male and female reproductive organs).Otherwise,the ovary development in Phalaenopsis flowers is triggered by pollination.So Phalaenopsis is the ideal material for floral development studies in monocots.Important progress has been made on molecular biology in the flower development of Phalaenopsis.In this review,the progress on the genes that are involved in flowering transition and floral organ development of Phalaenopsis are summarized.Also,the progress on the relationship between B-class genes and evolutionary development of orchid perianth is summarized.These researches indicated the MADS-box genes played important roles in the flowering transition and the floral organ development.It has been suggested that two rounds of DEF(DEFICIENS)-like gene duplications during early orchid evolution might have generated the genes that were probably recruited to distinguish the different types of perianth organs.The deep research of molecular biology in the flower development would greatly improve the flower quality such as flower color improvement and flowering time regulation by genetic engineering and promote molecular breeding process.