〔Abstract〕 Objective To investigate the effect and mechanism of overexpression of miR-370 on immune injury in asthmatic mice induced by ovalbumin(OVA). Methods 40 female BALB/c mice were divided into control group, model group(OVA), negative control group(OVA+miR-NC) and miR-370 overexpression group(OVA+miR-370). Except for the control group, the other groups were sensitized and stimulated to establish the asthma mouse model.After successful modeling, the OVA+miR-NC group and the OVA+miR-370 group were injected with miR-NC adenovirus and miR-370 overexpression adenovirus respectively by caudal vein. RT-PCR was commended to detect the expression level of miR-370, the bronchoalveolar lavage fluid(BALF) was collected, and Wright-Giemsa staining was used to determine the BALF number of leukocytes. Enzyme-linked immunosorbent assay(ELISA) was employed to detect the expression levels of immunoglobulin E(IgE) and immunomodulatory factor protein in BALF of asthmatic mice; hematoxylin-eosin(HE) staining and terminal labeling method(TUNEL) were used to observe the degree of lung tissue pathological damage and cell apoptosis; Western blot was used to detect the protein expression levels of Bax/Bcl-2 and cleaved cas3/cas3. Results Compared with the control group, mice in the OVA group expressed low miR-370(P<0.05), the number of leukagtes increased(P<0.05), the level of IgE increased(P<0.05), the levels of immunomodulatory factor γ-Interferon(INF-γ), interleukin-13(IL-13), interleukin-12(IL-12) and interleukin 4(IL-4) were up-regulated(P<0.05), and lung tissue was severely damage(P<0.05), the expression ratio of Bax/Bcl-2 and cleaved cas3/cas3 increased(P<0.05); Compared with the OVA group, there was no difference in the indicators of the OVA+miR-NC group. Ove-rexpression of miR-370 up-regulated the expression of miR-370(P<0.05), decreased the number of leukagtes(P<0.05) and the level of IgE(P<0.05), down-regulated immunoregulatory factors INF-γ and IL-12(P<0.05), up-regulated IL-13 and IL-4(P<0.05), and improved lung tissue damage, decreased cell apoptosis, and reduced the expression ratio of Bax/Bcl-2 and cleaved cas3/cas3(P<0.05). Conclusion Overexpression of miR-370 inhibits the production of BALF inflammatory cells in OVA-induced asthmatic mice and relieves lung injury in mice.