To explore the relationship between absorbed dose and fluorescence intensity, FAM-DNA-TAMRA (Carboxyfluorescein-oligonucleotide-carboxytetramethylrhodamine) aqueous solution of different concentrations combined with X-ray irradiation was used to measure the fluorescence intensity. The results showed that the linear relation between fluorescence intensity and absorbed dose was good for different-concentration FAM-DNA-TAMRA aqueous solution containing fluorescent probe in the dose range of 0−20 Gy. The fluorescence had good stability, but the fluorescence background affected the sensitivity of absorbed dose greatly. The results suggest that the FAM-DNA-TAMRA fluorescent probe can be used to measure the absorbed dose of aqueous solution.Cited