There are more than 2000 serotypes in the typhoid, septic and enteritidis Salmonella strains. This has long been a perplexity for the differentiation of Salmonella and discrimination from other food poisoning bacteria. In this research, we used polymerase chain reaction method （PCR） to develop a molecular technique for the detection of Salmonella. An invasion factor invA gene had been used to design the PCR primers. The results showed that under specific PCR conditions, many related bacterias such as Shigella, Yersinia, Serratia, Enterobacter, Vibrio and E. coli could be detected only with the primer annealing temperature ranging from 56℃~66℃. However, all tested Salmonella strains could be detected above 69℃. This is potential of being developed into a rapid method for detecting Salmonella strains in food or clinical specimens. In the future, it can be further increased the accuracy of detection in coordination with multi-primer PCR technique or developed into a biochip for the detection of Salmonella.