Abstract: At present, investment to reduce building energy consumption is about 5 times to reduce industrial energy investment, so the energy efficiency standards and technology economy of building is particularly important.Due to the fact that large number of universities in our country has become an important energy guzzler, using university existing buildings in cold area as research object, it was elaborated that by energy consumption surveys and testing data, simulation and analysis of existing building energy consumption, the key issues of existing building energy consumption could be found;the principle and technology system of energy efficiency retrofitting were established, which was the key to solve the problem of energy efficiency with university existing buildings.The use of technology should be on different characteristics of the existing buildings energy consumption and funds of retrofitting;flexible combination of technologies and applications was done;different levels of energy efficiency technology group were formed, which made the retrofitting be implemented truly.