Objective? To investigate the effects of fiberoptic bronchoscopic sputum aspiration combined with alveolar lavage on blood gas analysis indexes and inflammatory factors in patients with severe pulmonary infection. Methods A total of 170 patients with severe pulmonary infection who were admitted to People's Hospital of Deyang City from October 2019 to December 2020 were selected, they were divided into the control group and the observation group according to random number table method, with 85 cases in each group. Patients in the control group were treated with the conventional treatment of antiasthmatic, antitussive and anti-infection, nutritional support and mechanical ventilation, while the patients in the observation group were treated with fiberoptic bronchoscopic sputum aspiration combined with alveolar lavage on the basis of the conventional treatment of the control group, both groups were treated for 14 days. The clinical efficacy after treatment , the time for body temperature return to return to normal, the time for cough disappearance, the time for abnormal blood symptoms to improve, blood gas analysis indexes and inflammatory factor levels of patients in the two groups before and after treatment were compared. Results The total effective rate of the observation group was higher than that of the control group; temperature return to normal time, cough disappear time and abnormal blood symptom improvement time in the observation group were shorter than those in the control group; compared with before treatment, the level arterial oxygen partial pressure (PaO2) and blood oxygen saturation (SpO2) levels of patients in two groups increased after treatment, and the observation group was higher than that in the control group, while the arterial carbon dioxide partial pressure (PaO2) and serum tumor necrosis factor-α (TNF-α), the levels of procalcitonin (PCT) and C-reactive protein (CRP) levels of patients in the two groups decreased, and the observation group was lower than those in the control group (all P <0.05). Conclusion Fiberoptic bronchoscopic sputum aspiration combined with alveolar lavage in patients with severe pulmonary infection can effectively shorten the time of symptom improvement, improve clinical symptoms and respiratory function, reduce the level of inflammatory factors, and improve the curative effect.