This study focuses on construction and identification of immunized phage display library from splenocytes of hyperimmunized BALB/C mice for screening and isolation of scFv fragment against ENR,an alternative method to produce antibodies for veterinary drug residues detection.The total RNA was isolated from splenocytes of a BALB/C mouse hyperimmunized with the Enrofloxacin conjugated to chicken OVA.Variable light and heavy domains of the immunoglobulin genes were amplified by PCR and assembled to produce full-length single-chain Fv(scFV) by overlap extension PCR using a linker primer containing flexible polypeptide-(Gly3Ser)4.The scFv DNA fragment was ligated into phagemid vector pCANTAB5E and electroporated into E.coli XL1-Blue cells.The transformed cells were rescued by M13KO7 helper phage and phage libraries were constructed.The size of antibody libraries is 2.2×106.Following the construction of phage display scFv libraries,the recombinant phage displaying scFv were enriched and identified.There are 26 clones against ENR generated in this study.