Abstract: The genome DNAs of Salmonella and some control bacteria were extracted by boiling and CTAB/NaCl method, respectively. The concentration and purity of the DNAs isolated were estimated by spectrophotometric method and gel electrophoresis, and the results showed that the DNAs isolated by CTAB/NaCl method were better. Four pairs of primes were synthesized to amplify Salmonella genus special genes such as hut gene(495 bp), hilA gene(490 bp), invA gene(284 bp) and hns gene(152 bp) of Salmonella, respectively. The PCR reaction condition was optimized. The optimizing results showed that the PCR reaction condition fitting to amplify simultaneity the four genes of Salmonella was 94 ℃ initial denaturation 5 min; 94 ℃ denaturation 40 s, 60 ℃ annealing 40 s, 72 ℃ extension 50 s, 40 cycles; 72 ℃ final extension 5 min.

Key words: Salmonella, genome DNA, PCR, optimization