Anthrax is a zoonotic disease caused by infection with Bacillus anthracis. Pulmonary anthrax is the most lethal form, with a mortality of over 85%. As an emerging pathogen diagnostic technique, metagenomic next-generation sequencing (mNGS) has the advantages of detecting a wide range of specimens, covering a broad range of pathogen types, and having a short detection cycle. This paper reports a successfully treated patient who was diagnosed with pulmonary anthrax by mNGS testing of bronchoalveolar lavage fluid specimens. The patient, who had been engaged in processing raw wool for more than 20 years, was admitted to the hospital due to chest tightness, shortness of breath, and low fever for 3 days. Chest CT showed a possible tumor in the right lung and bilateral pneumonia. On the third day after admission, the patient’s breathing difficulty worsened and he was transferred to the intensive care unit. Considering the rapid progression of the condition and the unsatisfactory effect of empirical anti-infective treatment, mNGS testing of bronchoalveolar lavage fluid was performed, confirming the diagnosis of pulmonary anthrax. Combined with literature review and the clinical characteristics of pulmonary anthrax, this case suggests that mNGS has important value in the early diagnosis of complex infections and infectious diseases, which helps to facilitate timely targeted treatment in clinical practice.