To detect Salmonella spp. in suspect infected ducks, a loop-mediated isothermal amplification (LAMP) assay was developed. With the help of this assay, we can detect Salmonella enterica serovar Enteriditis and Salmonella enterica serovar Anatis above 6.0 cfu/test and 4.8 cfu/test, respectively, in pure-culture conditions, even in the existence of 0.01 g of duck liver or spleen homogenates; the detection thresholds were still achieved at 6.0 cfu per test tube. Further experiments of the test strains indicated the high specificity of this LAMP assay. In the detection of clinical specimens, a total of 115 Salmonella suspect infected clinical samples was analyzed by traditional culture method, LAMP, and PCR. The results suggested that 11 samples were positive by LAMP and culture methods; however, only 8 specimens were positive by PCR. In consideration of the high sensitivity and fast scanning speed of our LAMP method in clinical specimens, it was more suitable for field application and epidemiological investigation.