High affinity, fully human antibody fragment Fab that specifically bind to HGF receptor, Met (a proto-oncogene product and a key molecule on tumorigenesis, invasion and metastasis), was selected from phage display antibody library. To construct antibody library, the Fab gene fragment was constructed in 3 steps. The variable region genes were amplified from VH and VL of anti-Met Fab selected from error-prone PCR mutation library. Fab gene was assembled by overlap PCR and purified and digested with SfiⅠ, and inserted into pComb3XSS. Positive phage-displayed antibody clones were selected on live cell lines and immobilized protein. The purified Fab was verified by SDS-PAGE and Western blot, which showed two bands at about 25 ku and 27 ku at the expected sizes. To analyze the immunological characters of Fab for Met binding, flow cytometry and immunoprecipitation assays were set up and carried out with S114, MKN45 and NIH3T3 cell lines. The results demonstrated Fab could bind native Met specifically on the S114 and MKN45 cell surface. In vitro cytotoxic assay showed that only Hum-ZAP/anti-Met Fab complex could inhibit the Met positive cell growth, it illuminated that anti-Met Fab bound the Met on Met positive cell surface and were internalized. For Met negative cell line NIH3T3, no significant inhibition among the different dosages of Fab and Hum-ZAP. The results showed that anti-Met Fab antibody fragments could recognize Met extracellular domain in native conformation with relatively high affinity. Importantly, these antibody fragments were able to be internalized into Met over-expressed tumor cell lines through binding to the Met receptor, and could be applied as a potential powerful reagents for clinical therapy.