Construction of complex antibody libraries that expressed soluble antibody fragments on the surface of fd-phagemid with high screening efficiency subjected to rounds of in vitro mutadons. The individual antibody gene can then be affinity matured by emulating the process that occurs in B-cells in vivo .The affinity matured antibody fragments are selected for their ability to bind antigen after phage recovery. This novel recombinant DNA methods may replace the technology of using mice and hybridoma for the selection and production of antibodies.