Objective To study the change of immune factor in COPD rats after intravenous injection of regulatory T cells.Methods Twenty-one SPF rats was divided into three groups at random,rat COPD model was built by smoking.We used magnetic bead isolation technic to separate CD4+CD25+ regulatory T cells.Regulatory T cells were cultured and injected into rats though rats' caudal vein according to different dose,5 × 104/mL,5 × 105/mL,5 × 106/mL respectively.Flow cytometry was used to analyze cell factors.ELISA was used to analyze IL-6 and CRP.Restlts Adding JJ316 or IL-2 into medium benefited the proliferation of CD4+CD25+ regulatory T cells.On the 20 th day,regulatory T cells CD4+CD25+ proliferation stopped by adding JJ316 or IL-2 respectively.Regulatory T cells were cultured and injected into rats though rat caudal vein according to different dose.The levels of CRP and IL-6 were decreased when rats were injected by CD4+CD25+regulatory T cell after one week.Conclusions Injection of regulatory T cells is helpful to control inflammation progression of COPD,so the increase of regulatory T cells of patients with COPD may decrease inflammation progression of COPD.