This article presented a case of pulmonary infection caused by Actinobacillus ureae (A. ureae) in a patient with malignant tumor, along with a comprehensive literature review. During the patient’s hospitalization for chemotherapy, an opportunistic infection with A. ureae occurred, leading to typical pulmonary inflammation. The laboratory maintained consistent communication with clinicians throughout the diagnosis and treatment process, promptly conducting in vitro antimicrobial susceptibility testing on the pathogen and guiding standardized medication for the patient. Ultimately, following treatment with intravenous cefoperazone-sulbactam combined with levofloxacin for anti-infection symptomatic therapy, the patient’s pulmonary inflammation significantly improved. A literature review revealed that the infection rate of A. ureae was significantly higher than its actual detection level, suggesting that it should be considered one of the potential pathogens in susceptible patients in clinical practice. By reporting this case of pulmonary inflammation caused by an opportunistic infection of A. ureae, this article aims to raise awareness among laboratory staff about this pathogen and provide a reference for clinicians to timely diagnose and treat infections caused by rare pathogens.