Abstract: Objective　To explore the role of microRNA-206 in peripheral blood mononuclear cells (PBMC) in the pathogenesis and development of childhood asthma. Methods Twenty-seven asthmatic children and 25 healthy controls were enrolled in the study. Peripheral blood mononuclear cells were isolated in both healthy subjects and asthmatic children in acute attack and remission stages. Total RNAs were extracted from PBMC stimulated by PMA and ionomycin, and then the RNA was reversely transcribed into cDNA. The expressions of microRNA-206 and Kruppel-like factor 4 (KLF4) and IL-17 mRNA were detected by real-time quantitative PCR (qRT-PCR) method. Results There was significant difference of microRNA-206 levels among asthmatic children in attack stage and in remission stage and normal controls (F=46.58~72.81, P=0.000). Through pairwise comparison, the microRNA-206 levels of asthmatic children in attack stage were significantly lower than those in remission stage and normal control groups (P<0.01). The KLF4 and IL-17 mRNA levels of asthmatic children in attack stage were significantly higher than those in remission stage and normal control groups (P<0.01). There was no significant difference of miR-206, KLF4 and IL-17 mRNA between asthmatic children in remission stage and the healthy controls (P>0.05). Furthermore, a negative correlation was found between the expression of miR-206 and KLF4 (r=–0.66, P<0.01) and between the expression of miR-206 and IL-17 mRNA (r=–0.81, P<0.01) in asthmatic children in attack stage. A positive correlation was also found between KLF4 and IL-17 mRNA in asthmatic children in attack stage (r=0.70, P<0.01). Conclusions The expression of miR-206 is decreased in asthmatic children, and miR-206 might be involved in the pathogenesis and development of asthma.