Through the above studies, we confirmed miR-143-3p could improve mycoplasmal pneumonia by inhibiting inflammation response and cell apoptosis of alveolar epithelial cells in mice, and the mechanism may be that miR-143-3p can negatively regulate MyD88 expression in a targeted way, thus to negatively regulate TLR4/MyD88/NF-κB signaling pathway. Here, TLR4 is linked to Mycoplasma pneumoniae pneumonia.