ObjectiveTo investigate the effects of smoking on Th17/Treg T cell subsets and cytokines expression in patients with chronic obstructive pulmonary disease (COPD) in stable stage. MethodsFrom February 2012 to June 2013, sixty outpatients with stable COPD (20 cases of non-smokers, 40 cases of smokers) and 15 normal volunteers were recruited in the study in the Traditional Chinese Medicine Hospital affiliated to Xinjiang Medical University. Th17/Treg level in peripheral blood was detected by flow cytometry method. Cytometric bead array system was used to detect TGF-β, IL-10, IL-17A, IFN-γand other inflammatory factors in serum. ResultsThe patients' age, duration of disease, lung function, disease severity, and other related data were comparable between the smoking COPD group and the non-smoking COPD group (P > 0.05). Th17/Treg level was increased in the smoking COPD group compared with the normal group (P < 0.05), and showed an increasing trend from the normal group to the non-smoking COPD group and the smoking COPD group. The level of IL-2 in the smoking and non-smoking COPD groups was lower than that in the normal group. Compared with the normal group, the level of TNF-αwas significantly decreased in the smoking and non-smoking COPD groups(P < 0.05). ConclusionsSystemic inflammatory response continuously exists in patients with COPD even in the stable phase. Smoking can partly enhance the inflammatory reaction in COPD. The Th17/Treg T cell subsets associated cytokine regulation has gradually tended to a balance in the stable phase, and inflammatory factors related recovery speed is not consistent, suggesting that smoking may play a certain role in the recovery of balance.