The classical ABC model successfully illustrated the molecular mechanism of floral development in model species,such as Arabidopsis and Antirrhinum.Then,the ABC model was expanded based on new homeotic genes and mutants of floral organ found in other angiosperms.In this review,the different molecular models of floral organ development and the molecular regulation of homeotic genes are summarized and the prospects in this filed are discussed.This study is helpful for understanding the molecular mechanism and genetic basis of the floral development.