Abstract: Objective To explore the bacteria relevance between index fingers and contactant’ surfaces （mobile phone touch screen and desktop of personal office table）. Methods Bacteria were collected from the index fingers, mobile phone touch screen and desktop of personal office table of 10 volunteers. Enterobacterial repetitive intergenic consensus （ERIC）-PCR fingerprint was established by PCR amplification technique of metagenome. Results There were 7 volunteers’ ERIC-PCR fingerprints of index fingers matched that took from the mobile phone touch screens, and different from each other. There were 3 volunteers’ ERIC-PCR fingerprints of index fingers matched that took from desk top of personal office table, and other 7 volunteers’ ERIC-PCR fingerprints did not match perfectly with that took from desk top of personal office table, but had at least one similar band for both. Conclusion The bacteria on index finger shows individual specificity, which on mobile phone touching screen and personal desktop may be a new biological sample of forensic identification.

Key words: forensic genetics, polymerase chain reaction, DNA fingerprinting, enterobacterial repetitive intergenic consensus, finger print