Objectivie To develop a gene chip model containing 20 probes for detection of infections bacteria.Methods The probe of 16S rDNA and 2 synthesized oligonucleutide probes were employed to make gene chips by spoter.The DNA of bacteria was amplified by 16S rDNA universal primers and the PCR product was then applied to the gene chips for hybridization.A fluorescent scanner was used to observe and record the hybridization signals.Results The strains of bacteria were correctly identified in about 8 h.The cDNA microarray was very sensitive but less specific.Conclusion The accuracy and discrimination of the gene chip can be extended by adding further microbial probes without significantly increasing complexity or cost.