Three monoclonal antibodies against tumuor necrosis factor(TNF-α) were selected to biopan a 6-mer phage-displayed random peptide library. After biopannings, the enrichment of binding phages were estimated using a dot blot, ELISA, DNA sequence methods.These results showed that three to four rounds of biopanning could be enriched enough and the results also revealed that the screening of epitope would be easier with an antibody recognized a conformation-independent antigen than conformation-dependent one. Competitive ELISA assay and homological comparasion between the original antigen and the motifs were helpful to identification of epitopes.