【Abstract】 Objective To establish a simple, specific, sensitive PCR method with oral saliva sample to detect Helicobacter pylori and evaluated the sensitivity and specificity for detection of the helicobacter pylori infection in the clinical field. Methods Primers and probes were designed by corresponding to the converse 16s rRNA gene sequences and which were matched by Blast method in Genebank and then. The excellent primers and probes were selected. Electrophoretic analysis of the PCR products was amplified by different annealing temperature and different reaction system. The best reaction conditions were determined. The counted Hicobacter pylori in bacterium suspension and oral saliva mixture were serially diluted. The gene was extracted, and amplificated by real time PCR. The sensation was evaluated, and the standard curve of the colony form unit (CFU) counts corresponding to the real time PCR cycle numbers were established. The genes of pathogens, such as Lactobacilli strain, Saphylococcusaureus, Neisseriaceae, B. denticola and S. salivarius were used for specificity test. The saliva samples of 150 patients were detected by real time PCR and compared the results with the URT. Results The primer annealing temperature at 62℃ and reaction volume was 10μl. Its sensitivity was able to detect 102 CFU/ml of Hicobacter pylori and no cross reaction with Lactobacilli strain, Saphylococcusaureus, Neisseriaceae, B. denticola and S. salivarius. The sensitivity compared with URT was 74.12%, specificity was 8615%, the coincidence rate was 7933% and Kappa was 059,respectively. Conclusion A new gene saliva diagnosis method to Helicobacter pylori was established. The limit of detection(LOD) to Hicobacter pylori was 102CFU/ml and no cross reaction with other pathogens. The sample was saliva which could give the doctor a new sensitive, specific, rapid, noninvasive and available diagnostic tool to detect Helicobacter pylori in oral cavity.