Cytochrome P450s are heme-containing mixed-function oxidases,involving in lots of biochemical reactions. They play an important role in preventing plants from pathogen and insect attacks and environmental stress. Sequence analysis of genomes has revealed that P450 is a gene super-family. Many cytochrome P450s have been characterized and cloned. Some of them have been used in plant genetic improvement. A great progress has been made in using these P450 genes to create the transgenic plants with multiple resistances,male sterility, higher capability to dissolve toxic chemicals and pollutants and effective productivity of high valuable compounds,indicating P450 genes have a broad prospect with great potential application.