With the rapid development of the global economy, the world energy consumption is increasing day by day. Mankind is facing the problem of energy shortage. Energy conservation and emission reduction has become the focus of countries all over the world. In order to study the influence of building envelope on building energy efficiency in severe cold area, the sensitivity analysis is used to analyze the influence relationship between building envelope and building energy efficiency. Combined with DeST simulation software, the building model is established, and the arc mean elasticity method is used to analyze the sensitivity of building energy load to different building envelope parameters. The results show that the external windows of the building envelope have the greatest impact on the building energy efficiency, followed by the external walls, and the roof has the least impact on the energy efficiency. The sensitivity coefficients of the annual cumulative load to the external windows, exterior walls and roofs of buildings are 7.93%, 5.76% and 5.75% respectively. Studying the influence of enclosure structure on building energy efficiency in severe cold areas has important practical value for reducing building energy consumption in severe cold areas and provides data reference for scientifically improving building energy efficiency and building skill transformation in severe cold areas.