Tuberculous meningitis (TBM) is the most common and severe form of central nervous system tuberculosis, characterized by high mortality and morbidity rates. However, its diagnosis and treatment remain challenging, posing a significant threat to global health. Clinically, the high fatality and disability rates associated with TBM are attributed to multiple factors, including nonspecific clinical manifestations, lack of rapid and sensitive diagnostic tests for early detection, frequent misdiagnosis due to coinfection with other pathogens, the emergence of multidrug-resistant tuberculosis (MDR-TB), and limited blood-brain barrier penetration of antitubercular drugs. This article summarized a case of TBM incidentally diagnosed during COVID-19 screening. A patient presenting with coma underwent cerebrospinal fluid (CSF) smear examination and related laboratory tests. A positive result of acid-fast staining of CSF prompted a rapid clinical diagnosis of TBM. Although molecular diagnostic techniques for TBM demonstrate superior sensitivity and specificity, traditional CSF acid-fast smear microscopy retains unique advantages, such as simplicity, rapid turnaround time and low cost, making it a critical diagnostic tool in resource-limited settings. This study recommends integrating smear microscopy, molecular testing, and culture techniques in clinical practice to establish a stepwise diagnostic framework for TBM.