In the present paper,the authors studied fluorescence resonance energy transfer (FRET) phenomenon between silver triangular nanoplates and bovine serum albumin (BSA)/Rhodamine 6G fluorescence complex,and established a fluorescence method for the detection of cobalt ions.We found that when increasing the silver triangular nanoplates added to certain concentrations of fluorescent bovine serum albumin (BSA) /Rhodamine 6G complex,the fluorescence of Rhodamine 6G would be quenched up to 80% due to the FRET between the quencher and donor.However,in the presence of cobalt ions,the disassociation of the fluorescent complex from silver triangular nanoplates occurred and the fluorescence of the Rhodamine 6G recovered.The recovery of fluorescence intensity rate (I/I0) has a good relationship with the cobalt ion concentration (cCO2+) added.Thus,the authors developed a fluorescence method for the detection of cobalt ions based on the FRET of silver triangular nanoplates and Rhodamine 6G.