Abstract: This study was conducted to test the hypotheses that dietary L-arginine supplementation may enhance the immune responses and resulting in the clearance against PCV2 in experimentally infected mice. The measured variables include: the PCV2 virus load in liver, spleen, heart, lung, kidney, ovary and serum on 3rd, 5th, 7th, 9th and 11th day post infection (dpi); serum Interleukin-2 (IL-2), Interleukin-6 (IL-6), Interleukin-10 (IL-10), Interferon alpha (IFN-α), Interferon gamma (IFN-γ) and C-Reactive Protein (CRP) levels on 3rd, 5th, 7th, 9th and 11th dpi; serum Total Superoxide Dismutase (T-SOD) activity on 3rd, 5th, 7th, 9th and 11th dpi. Results showed that arginine supplementation could significantly increase the serum IL-2 levels on the 9th and 11th dpi; significantly increase the serum IFN-α and CRP levels on the 11th dpi; significantly increase the serum IFN-r levels on the 7th dpi and significantly decrease the serum IL-6 levels on the 9th dpi. Meanwhile, the PCV2 virus genome was detected sporadically. Collectively, dietary L-arginine supplementation had beneficial effects on the cytokines profile in the PCV2 infected mouse and maybe could delay the PCV2 replication and/or clear the PCV2 in mouse model.