Although　external　wall　thermal　insulation　layer　protects　the　major　structure　effectively　and　is　capable　of　the　prolonging　of　the　service　life　of　the　structure,　building　thermal　insulation　material　production　brings　environmental　impact　in　some　degree.　In　this　research,　quantitative　analysis　and　evaluation　of　resources　consumption　and　pollutant　emission　caused　by　materials　on　external　wall　were　carried　out　based　on　Life　Cycle　Assessment　(LCA).　The　results　show　that,　environmental　load　brought　by　rock　wool　board　production　has　a　decisive　influence　on　the　total　environmental　load　of　the　external　thermal　insulation　system　production.