The aim is to investigate the effects of low-dose γ-rays on gene expression of BTG2 and the probability of it as bio-dosimeter. AHH-1 lines were irradiated with ?-rays of 0−1.0 Gy. Total RNA of cells was extracted at 0−168 h after irradiation, and real-time quantitative PCR was used to detect BTG2 gene expression. The relationships between the dose or time and gene expression were analyzed. After irradiation, the BTG2 gene expression increased in a dose-dependent form. Its peak expression was at 24 h after irradiation, and then the BTG2 gene expression gradually decreased to platform stage at 48 h and 72 h, and finally returned to the level of 0 h at 168 h. BTG2 gene is sensitive to irradiation and has potential in usage as biological dosimeter for its good dose and time-effect relationships.Cited