Objective: To understand the sanitation status of teaching environment of schools in Beijing, and to provide basis for school environmental improvement through monitoring it. Methods: In 2019, 661 primary and secondary schools were selected according to the coverage rate of 50% of all schools. Two classrooms were randomly selected from each school for testing, 1 322 classrooms were monitored. The testing contents included per capita area of the classroom, rate of correct desks-chairs adjusting for school height, blackboard size, reflection ratio of blackboard,illumination, carbon dioxide and noise. Results: The qualified rate of noise(92.3%), per capita area(86.5%), blackboard size (85.6%) and illumination uniformity of table top (83.4%) were higher than 80%, while the qualified rate of other indexes were lower than 80%. In 2019, the qualified rate of blackboard size, blackboard average illuminance and blackboard illuminance uniformity were higher than 2018 year(85.6%, 52.7%, 36.2%; 81.9%, 42.7%, 31.7%)(χ2=10.97, 7.80, 5.90, P<0.05), while the noise (92.3%) was lower than 2018 year(98.3%)(χ2=70.82, P<0.05). Both classroom and blackboard, the average illuminance and evenness of the desk and blackboard installed with LED light were higher than those installed with fluorescent lights. Conclusion Teaching environment monitoring in Beijing is not optimistic. It is necessary to strengthen the promotion and evaluation of standards,and the classroom environment needs to be further improved.