The energy consumption of building is relatively high in China. The air tightness is an important factor affecting the energy consumption of building. In order to study the method of overall air tightness test of large-scale buildings,taking a new large-scale building in a cold area of China as an example,the process and key points of the air tightness test of large-scale buildings were introduced in detail from the aspects of enclosure structure plugging measures,regional division,calculation of air leakage limits,and layout of measuring points. Put forward to use partition testing method to test the air tightness of large buildings and obtain the actual measured value of the overall airtightness of the tested building. The test results indicate that using partition testing method for air tightness testing of large buildings can reduce the limitations of equipment and the influence of external environmental factors. Provide reference and suggestions for conducting air tightness performance testing,improving building construction,shortening testing cycles,and performance evaluation for large-scale buildings.