Abstract: Bacterial pneumonia is a common clinical disease and the abuse of antibacterial leads to the production and prevalence of resistant bacteria. Novel antibacterial active ingredients can be found from natural products for the treatment of bacterial pneumonia. Pulmonary delivery systems can directly deliver drugs to infected lung tissues, favoring the treatment of bacterial pneumonia. Cinnamon oil (CO) is a volatile oil extracted from cinnamon, which has antibacterial and anti-inflammation functions. However, the preparation of its pulmonary delivery systems is difficult because of its oil and volatile properties. Here, CO-β-cyclodextrin inclusion complex (CO-β-CD) was prepared. Its dry powder inhalers (DPIs) were obtained by lyophilization. The DPIs had the aerodynamic diameter of 1.34 μm and the fine particle fraction (FPF) of 30.90%, which was suitable for pulmonary delivery. The minimal bactericidal concentration of CO-β-CD was 2 mg·mL^-1 against Staphylococcus aureus (SA). The animal experiments were approved by the Ethics Committee of Academy of Military Medical Sciences and the experiments were conducted in accordance with relevant guidelines and regulations. A high intratracheal (i.t.) dose (100 mg·kg^-1) of CO-β-CD did not show significant toxicity to the mice. Bacterial pneumonia mice models were established after intraperitoneal injection of dexamethasone and then i.t. administration of SA. CO-β-CD and penicillin were separately i.t. administered to the mice. Both of them alleviated the lung injury of mice and remarkably increased the survival rates. Compared to penicillin, CO-β-CD significantly reduced the infiltration of inflammatory cells and the numbers of leukocytes and neutrophils in the blood, and the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the lung tissues were similar to those of the healthy mice, indicating that CO-β-CD had the capability of anti-inflammation besides antibacterial effect in vivo. CO-β-CD dry powder inhalers are a potential pulmonary delivery system for the treatment of bacterial pneumonia.