The gene expression changes of rat blood lymphocytes after 2.0 Gy γ-ray irradiation were studied. At 24 h after in vitro and in vivo irradiation with 2.0 Gy 60Co γ-ray, RNA in blood lymphocyte was extracted and the changes in the gene expression profiles of lymphocytes were detected. The results showed that at 24 h after irradiation, the common genes being significantly expressed in in vitro and in vivo comprised 1,322 genes, including 497 down-regulated genes and 633 up-regulated genes. Further, 192 genes are inconsistent. Referring to the GO database, there are 53, 19, 28 functional clusters involved in biological processes, cellular components and molecular functions, respectively, and there are 12 pathways involved. In addition, some radiation-related genes such as Serpinb2, Creb3l2, Pacrg, Vamp1, Il16, and others were also found.Cited