A fluorescence biosensor to detect salmonellae was established based on metal organic frameworks(MOFs) and aptamer.Uio-66-NH2 material has a strong adsorption capacity for FAM labelled aptamers and could completely quench the fluorescence of FAM.The aptamer of nucleic acid has high affinity and high specificity.In the presence of salmonellae,the binding between the FAM labelled aptamer and salmonellae will alter the conformation of FAM labelled aptamer.Therefore,the interaction between the FAM labelled aptamer and MOFs would be disturbed.Such interactions will cause the releasing of the FAM labelled aptamer from the Uio-66-NH2 material,resulting in the restoration of FAM fluorescence.And this method was applied to the estimation of salmonellae in shrimp samples,with the recoveries of 900%-1080%.The fluorescence intensity of the system has a linear relationship with the logarithm of salmonellae concentration in the range of 101-105 cfu/mL,with a detection limit(S/N=3) of 7 cfu/mL.The experimental results showed that the biosensors had a high sensitivity and a high selectivity to salmonellae.