Taking the existing buildings as the research object,this paper reviews the research status of the ex-ternal thermal insulation system of the existing building in recent years,and focuses on the method of perfor-mance testing,current situation evaluation,case analysis,and the implementation and effect of renovation mea-sures of the thermal insulation system. Through the in-depth analysis of a number of cases,the renovation mea-sures for the external wall insulation system of existing buildings in cold areas are proposed,which provides reference for practice and research in related fields.