Abstract: Objective To analyze the relating factors of school cluster of pulmonary tuberculosis (TB) and provide evidence for pulmonary tuberculosis control and prevention in school. Methods Chest X ray examination and chest radiography were performed in all classes with TB cases, and PPD test was conducted in some classes. Sputum smear test and acid-fast bacillus test were conducted among the students with abnormal results of X ray examination. Results Twenty-six pulmonary TB cases were detected. The first case was misdiagnosed as chronic pharyngitis in 3 months. The cluster was observed in the class and dormitory in which the first case occurred (P＜0.01). The detection rate of TB by chest X ray examination was 0.10%, the detection rate by tuberculin test and chest radiography was 40.48%. Conclusion The cluster was caused by the misdiagnosis and delayed isolation of the first case. It is essential to strengthen the management of communicable disease in school, conduct the registering of school absence of students and teachers as well as their disease causes and integrate the effect of hospital, school and disease control and prevention system for the effective prevention and control of school cluster of pulmonary TB.