This paper reports a case of pulmonary infection caused by Corynebacterium striatum in an elderly patient. The patient, male, 93 years old, was treated with piperacillin-tazobactam, imipenem-cilastatin and levofloxacin due to “aspiration pneumonia” two months ago. The patient’s pulmonary infection was difficult to control, and meropenem was upgraded for anti-infection, but the effect was not good. After empiric antifungal treatment with fluconazole, the pulmonary infection continued to persist and the symptoms worsened. Sputum culture result suggested Corynebacterium striatum (＋＋＋＋), and linezolid showed a large diameter inhibitory zone against the bacteria. Considering the previous treatment plan was not satisfactory, fluconazole was discontinued and the regimen was adjusted to meropenem combined with linezolid for anti-infection. Ten days after the adjustment of the antimicrobial agents, the patient’s symptoms of cough and sputum production gradually improved. Subsequently, meropenem was de-escalated to levofloxacin combined with linezolid for anti-infection. After 2 days of de-escalation therapy, the patient’s pulmonary infection improved, and the antimicrobial agents were discontinued, resulting in successful treatment of the pulmonary infection.