In September 2020, three pulmonary tuberculosis cases were identified during school physical examinations at a senior high school in a district (School B) of Hangzhou City. Immediate epidemiological surveys were performed by local district and Hangzhou Center for Disease Control and Prevention, and a pulmonary tuberculosis outbreak involving 9 cases in 6 schools were identified. All cases were once Grade 9 students in Class of 2019 at a junior high school (School A), and the source of infection might be a laboratory-confirmed cases (index case) in this class reported in April, 2019. Following exposure to index case, other cases developed disease onset or were screened after entering senior high schools. In November, 2020, tuberculin skin test and chest X-ray scan were performed to screen pulmonary tuberculosis among 43 students and teachers in a class of Grade 9 in Class of 2019 at School A, and 17 students strongly positive for tuberculin skin test were given prophylactic therapy. No pulmonary tuberculosis case were identified until June 2021. It is suggested that early epidemiological surveys facilitates the identification of the epidemiological correlation between cases. Active search for individuals with common exposure history and prophylactic therapy are required if a possible outbreak is found, which is helpful to avoid the spread of the outbreak.