Phospholipase D2 (PLD2) enzymes are expressed on the cytoplasmic membrane of bacteria, fungi, plants, and animals and have been linked to many critical cellular processes. Recently there are lots of research results about PLD2 that are associated with chronic inflammation activity of cells. To evaluate the potential influence of PLD2 on asthma, a self-made protein including the main functional domains of PLD2, named recombinant human phospholipase D2 (rhPLD2), was designed in our lab. The effects of rhPLD2 on mucosal inflammation were examined by hematoxylin and eosin staining in an ovalbumin (OVA) induced murine model of asthma. Cytokine concentrations in BALF obtained from mice were measured using ELISA kits. The ratio of T-bet and GATA-3 expression level in spleen and lymph nodes after rhPLD2 administration was also assessed through RT-PCR. It demonstrated OVA-induced mice exhibited elevated pulmonary eosinophilia and allergic inflammation in the airways along with increased expression of IFN-γ, IL-4 in the lung BALF. RhPLD2 could alleviate lung inflammation and reduce significantly the number of eosinophils in peripheral blood and BALF. RhPLD2 could reverse IFN-γ/IL-4 ratio in lymphocytes of BALF, lung, spleen, lymph nodes of asthma mice on genetic level. Treatment of asthma mice with rhPLD2 in vivo directly increased the frequency not only of IL-10+Treg cells, but also of CD25+ Treg cells in peripheral blood. From a therapeutic point of view, rhPLD2 alleviates allergic airway Inflammation via balancing Th1/Th2 Homeostasis and increasing Treg cells and has been shown to function in immunoregulatory activities in OVA-induced asthma mice.