Objective: To understand the trend of changes of hygiene status in the teaching environment among primary and secondary schools in Beijing City during 2016-2020, so as to provide basis for further improving the teaching environment and campus hygiene conditions in primary and secondary schools. Methods: A proportional systematic sampling method covered over 50% of schools selected annually in Beijing from 2016 to 2019, and 34% were selected in 2020. Two representative classrooms were selected from each selected school for testing based on their structure and other factors, with 6 196 classrooms supervised, from 2016 to 2020,1 330,1 312,1 384,1 322,848 classrooms were monitored for each year. Results: From 2016 to 2020, the overall lighting qualification rate of classrooms (lighting coefficient 72.8%, window to floor area ratio 41.8%, rear wall reflectance ratio 42.2%, blackboard reflection ratio 37.4%), the overall qualification rate of average blackboard illumination and uniformity (50.6%, 34.9 %), and the overall qualification rate of desk and chair allocation (58.6%) were all below 80%. The overall qualification rate of per capita classroom area (87.5%), blackboard size (83.2%), average desk illumination ( 80.1% ), average desk illumination and uniformity (82.9%), the distance between lamp and desk (99.1%), carbon dioxide ( 86.6% ), temperature (84.9%), and noise (96.6%) were all above 80%. The following indicators, blackboard size, the distance between lamp and desk, average blackboard illumination, lighting coefficient, blackboard reflectance, rear wall reflectance, carbon dioxide, temperature, and noise ( χ 2=78.38, 9.71, 11.76, 320.59, 37.63, 58.45, 236.45, 1 347.56, 101.97), had statistically significance between years. Among those indicators, the qualified rates of blackboard size, blackboard reflectance, lighting coefficient, and noise had been increasing year by year ( χ 2 trend =69.98, 15.82, 240.02, 5.77) ( P <0.05). The qualified rates of per capita classroom area, window to floor area ratio, and blackboard reflection ratio in primary schools (81.6%, 39.8%, 36.3%) were all lower than those in secondary schools (94.9%, 44.5%, 40.3%) ( χ 2=246.32, 12.03, 10.51, P <0.05). The qualified rates of blackboard size, average blackboard illumination, average blackboard illumination and uniformity, and desk and chair allocation (89.3%, 55.6% , 36.0%, and 60.2%) were all higher than those in secondary schools (75.4%, 44.1%, 33.3%, and 56.5%) ( χ 2=209.33, 78.41, 4.44, 8.22) ( P <0.05). The qualified rates of average desk illumination and uniformity, average blackboard illumination, rear wall reflectance ratio, desk and chair allocation, carbon dioxide, temperature, and noise indicators in urban area (82.9%, 84.1% , 51.9%, 45.0%, 60.9%, 91.2%, 89.5%, 97.8%) were all higher than those in suburban area (77.3%, 81.7%, 49.2%, 39.5%, 56.3%, 82.3%, 80.4%, 95.5%) ( χ 2=31.16, 6.28, 4.36, 16.40, 13.39, 105.29, 98.23, 24.66， P <0.05). The qualified rates of the distance between lamp and desk, lighting coefficient, window to floor area ratio, blackboard size, blackboard reflection ratio, average blackboard illumination and uniformity, and per capita classroom area in urban areas (98.8%, 65.2%, 34.3%, 76.7%, 35.9%, 30.1%, 84.6%) were all lower than those in suburban areas (99.4%, 81.4%, 49.8%, 89.7%, 40.2%, 39.6%, 90.3%) ( χ 2=6.80, 171.67, 132.43, 188.46 , 12.45, 60.28, 44.82) ( P <0.05). Conclusions The main problems in the teaching environment of schools in Beijing are classroom lighting, as well as desk and chair allocation. The findings suggest technical rationality and operability of relevant standard should be considered when under revision, and standard training and supervision management should be strengthened, with the aim of teaching environment improvement.