Abstract:Flower development can be distinguished by three phases: flowering determination, flower evocation, and floral organ development. Several pathways regulate the switch from vegetative to reproductive development, including photoperiod, light quality, vernalization, autonomous pathway, gibberellin, and carbohydrates induction, while repression pathways also exist in plants. Distinct inductive pathways can activate the expression of flower meristem identity genes, thus cause the transition from shoot apical meristem to flower meristem. Floral organ development is controlled by floral organ identity genes, whose exact expression was activated by flower meristem identity genes and controlled by various positive and negative regulators. In addition, there is a kind of genes that determine the symmetry of flower. Research on the mechanism of flower development can contribute to the basic theory research as well as later application.