Abstract: RNA interference is an evolutionarily conserved defense mechanisms to resist transgenic genes and alien virus, it lies in many different species of organisms, and can transfer between organisms cells with the effect of resisting virus invasion and maintaining genome stahility. RNA interference library is based on RNA interference technology with the feature of the simplicity, efficiency, large- scale and high throughput, can be used in large scale screening of gene function and phenotype screening. Research and application of RNA interference as an extremely important theoretical and practical significance of the medical biology will have a profound impact on development.