Objective To measure the organ weights, blood physiological and biochemical parameters, and immune function of Specific Pathogen Free (SPF) Rag2 knockout (KO) mice. Methods Rag2 knockout mice were selected at five and ten weeks, and the organ weights, blood physiological and biochemical parameters were observed. The percentages of CD3+, CD4+, CD8+, CD19+, B220+, NK1.1+, and CD11b+were checked by FCM in Rag2 KO mice at six week of age in terms of its T, B lymphocyte function and NK cell activity. Results Among the same sex group of NOD/SCID mice, the weights of brain, lung, spleen, liver, heart, kidney, and the levels of TBIL, WBC in 10 weeks of age are higher than 5 weeks. At the same age, the weights of heart, kidney, liver, spleen, and the levels of AST, ALP, A/G, GLU, PLT, PCT, WBC, and LYM% in male mice are higher than females. The Rag2 KO mice lacks T cells(0.36±0.15)%、CD4+T cells(0.21±0.06)%、CD8+T cells(0.23±0.07)%、CD19+B cells(0.28±0.04)%、B220+B cells(2.03±0.42)%). The percentage of NK cells is(24.13±3.62)%, and the percentage of granulocytes is(57.20±3.85)%. Conclusion The study suggests that the organ weights, blood physiological and biochemical parameters are affected by age and gender in Rag2 KO mice, which main biological characteristics are similar with C57BL/6J mice. The Rag2 KO mice show the deficiency of T, B cells function.