This paper reports a case of brain abscess caused by Streptococcus constellatus. The patient, a 54-years-old male with double vision for 19 days, was treated with anti-tuberculous therapy based on nuclear magnetic resonance imaging (MRI) findings that did not exclude the formation of tuberculosis balls from tuberculosis infection. Metagenomic sequencing of the cerebrospinal fluid was also performed, and the results showed that Campylobacter recti and Fosetylastanella were the main causative organisms. On follow-up history, the patient had periodontal disease and recent significant left-sided maxillary pain. After reviewing the literature, there were reports of intracranial abscesses caused by Campylobacter recti, so anti-tuberculosis treatment was stopped and moxifloxacin antibacterial therapy was used instead. The patient's headache and discomfort worsened, and the MRI was repeated again, suggesting gradual expansion of the lesion and rapid change of the condition, and the cerebellar occupying lesion was removed urgently. Brain abscess with tissue culture resulted of Streptococcus constellatus. The patient was discharged from the hospital in stable condition after comprehensive treatment with linezolid anti-infective therapy according to drug sensitivity.