Objective To compare the urine aquaporin 2 (AQP2) levels between asthmatic patients and healthy participants, explore the AQP2 levels in patients with asthma of different clinical control levels and its relationship with inflammatory factors. Methods Urine AQP2 levels were examined by ELISA in 60 patients with asthma and 21 healthy participants; plasma interleukin (IL)-4, IL-6, tumor necrosis factor (TNF)-α and interferon (IFN)-γ levels were determined by by CBA method. Results The levels of urine AQP2 in clinical uncontrolled asthma group (ACT below 19) and partially controlled asthma group (ACT 20~24) were significantly higher than that in the healthy control group(P<0.01), and the level in the uncontrolled group was (174.28±40.81)pg/mL. The plasma IL-4 level in uncontrolled group was (1.10±0.25)pg/mL, which was significantly higher than those in the other two groups (P<0.01). The plasma IL-6 level in uncontrolled asthma group was the highest but showing no significant difference when compared with the other two groups(P=0.058). The TNF-α level in asthma patients was significantly higher than that in healthy controls(P<0.05). Urine AQP2 was found significantly correlated with plasma IL-4 and IL-6 levels(P=0.049,P=0.010); plasma IL-4 level was significantly correlated with IFN-γ level(P=0.019); IL-6 was significantly correlated with TNF-α level(P=0.010); and IL-10 was significantly correlated with IFN-γ levle(P=0.005). Conclusion Urine AQP2 level of asthma patients is increased, and it is significantly correlated with plasma levels of inflammatory factors IL-4 and IL-6. The role of AQP2 in the pathogenesis of bronchial asthma is worth further studying.