In extremely cold areas with long winter months and exceptionally cold weather, classrooms are inadequately ventilated, resulting in the continuous accumulation of indoor air pollutants that may endanger human health. This article uses adsorption tube sampling-thermal desorption-gas chromatography mass spectrometry to analyze the type and concentration of volatile organic compounds (VOCs) in the classroom. The source analysis and health risk assessment were performed, and the real-time concentration of total volatile organic compounds (TVOC) was computed using the multifunctional ventilation. The result shows that the air in the classroom contains 25 kinds of VOCs. Among them, the carcinogenic risk value of seven kinds of VOCs (3.40 × 10-5) exceeds the acceptable risk value (1 × 10-6) given by the U.S. Environmental Protection Agency (US EPA). There are 17 kinds of VOCs that pose a certain non-carcinogenic risk to the human body. After quantitative analysis by the principal component analysis (PCA) and the characteristic quantity concentration ratio method, human activities, furnishings, outdoor penetration, etc., were found to be main sources of VOCs in the classroom. In addition, TVOC concentration is directly proportional to class time. In winter, classrooms in severely cold areas must take necessary measures to reduce the concentration of VOCs and ensure students' health.