As the defects of the existing detection methods for Salmonella, a fast, simple, low cost and highly sensitive new rapid detection technology has been developed. The CdTe quantum dots were synthesized by water method, and then the display DNA was used to connect hundreds of quantum dots to a gold nanoparticle. After preparing the amination Fe₃O₄ magnetic nanoparticles by using a water hot-solvent hot method, the principle of avidin-biotin specific was used to bind with the capturing probes. Finally the fluorescence intensity of Salmonella DNA was detected. The results showed that the fluorescence intensity and Salmonella DNA concentration had good linear relationship in the range of 10～1 000 fmol/L, and the regression equation was I_F=0.198 \[DNA\]+55.00, R²=0.997, with the detection limit of 8 fmol/L. Moreover, it also showed good accuracy, with the minimum detection limit of 4 fmol/L, in the detection of milk samples contaminated with salmonella.