Abstract: Pediatric actinomycete infection is extremely rare without typical clinical symptoms. It is easily misdiagnosed as fungi, tuberculosis and tumors based on imaging findings. In this article, the diagnosis and treatment of a child with pulmonary actinomycete infection were reported. A 7-year-old boy presented with fever and cough. Routine blood test showed significant elevation in the white blood cells and C-reactive protein. CT scan of the lung suggested lung infection. The possibility of other special floral infection, such as fungus, should be excluded. After 1-week routine anti-infection treatment, no significant changes were detected in the imaging findings of the lung. Bronchoscopy was performed to obtain the alveolar lavage fluid for subsequent metagenomic sequencing, which prompted actinomycete infection. After the diagnosis was confirmed, he was administered with intravenous high-dose penicillin. After discharge, amoxicillin/clavulanate potassium was orally given for nearly two months. CT scan revealed significant improvement. The diagnosis and treatment of this case indicate that metagenomic sequencing from alveolar lavage fluids contributes to early diagnosis of pediatric pulmonary actinomycete infection. Full-course of high-dose penicillin can achieve high clinical efficacy.