Paeoniflorin has been demonstrated to exert anti-inflammatory and immunomodulatory effects in the animal study. In this study, we investigated immunoregulatory effects of paeoniflorin on anti-asthmatic effects and underlying mechanisms. Asthma model was established by ovalbumin-induced. A total of 50 mice were randomly assigned to five experimental groups: control, model, dexamethasone (2 mg/kg), and paeoniflorin (10 and 20 mg/kg). Airway resistance (Raw) were measured by the forced oscillation technique; histological studies were evaluated by the hematoxylin and eosin (HE) staining; Th1/Th2 cytokines were evaluated by enzyme-linked immunosorbent assay (ELISA); Th1/Th2 cells were evaluated by flow cytometry (FCM); and GATA3 and T-bet were evaluated by Western blot. Our study demonstrated that, compared with model group, paeoniflorin inhibited ovalbumin (OVA)-induced increases in Raw and eosinophil count; interleukin (IL)-4, IgE levels were recovered in bronchoalveolar lavage fluid compared; increased IFN-γ level in bronchoalveolar lavage fluid; histological studies demonstrated that paeoniflorin substantially inhibited OVA-induced eosinophilia in lung tissue and lung tissue compared with model group. Flow cytometry studies demonstrated that paeoniflorin can regulate Th1/Th2 balance. These findings suggest that paeoniflorin may effectively ameliorate the progression of asthma and could be used as a therapy for patients with allergic asthma.