In pH 7.4 borax-boric acid buffer solution and in the presence of NaCl,gold nanoparticles（GNPs） interacted with kanamycin aptamer to form a stable nanogold-aptemer complex.When kanamycin was added in the solution,it could interact with the aptamer to form a more stable composite while GNPs were released.The uncombined GNPs aggregated into large clusters,which could cause the increase of resonance Rayleigh scattering（RRS） intensity at 571 nm in high concentration of NaCl.Effects of pH value,NaCl concentration and reaction time on the resonance scattering intensity were studied.Moreover,influences of different aptamers and coexistent substances on the determination were also investigated.The results showed that the method had good selectivity.Under the optimum conditions,the increased RRS intensity was linear over kanamycin concentration range of 0.02-0.3 mg/L,with a correlation coefficient（r） of 0.995 6 and a detection limit（3σ） of 2.3 μg/L.The method was applied in the determination of kanamycin in kanamycin injection with satisfactory results.