The invention relates to a salmonella and shigella joint detection kit and a detection method thereof. The kit of the invention comprises Bst DNA polymerase, buffer solution, dNTPs, betaine, magnesium sulfate, development solution, stabilizing solution and positive control; and the kit also comprises two pairs of primers, namely inner primers FIP/BIP and outer primers F3/B3 which take salmonella AgfA genes and shigella ipaH genes as target genes and are designed based on loop-mediated thermostatic amplification technology. The salmonella and shigella detection kit has the advantages of more comprehensive detection effect, high specificity and low omission factor, and is suitable for quickly detecting salmonella and shigella in physical examination of food employees.