The cDNA encoding keratinocyte growth factor-2 was isolated from human fetal liver cDNA library and subsequently cloned into the bait protein plasmid pAS2-1.The positive clone was obtained from human fetal liver cDNA library screened by yeast two-hybrid system. After sequence analysis and homology comparison, the candidate protein was identified as human ribosomal protein L22.KGF-2 and the candidate proteins were separately cloned into BD and AD plasmid of mammalian two-hybrid assay and cotransfected into COS-7 cell line. The interaction between KGF-2 and the candidate protein was identified by CAT assay.