Though　the　thermal　conductivity　of　phase　change　energy　storage　plasterboard　was　usually　tested　by　unsteady　method,　a　stable　method　was　proposed　to　investigate　the　change　of　thermal　conductivity　of　phase　change　energy　storage　plasterboard.　Two　testing　methods,　steady　state　test　method　of　protection　hot　plate　method　and　unsteady　test　method,　were　compared　in　the　measurement　of　the　thermal　conductivity　of　the　phase　change　energy　storage　plasterboard　with　the　same　proportions.　By　the　analysis　and　comparison　of　the　two　kinds　of　test　methods,　the　thermal　conductivity　will　decrease　with　the　addition　content　of　phase　change　materials　increasing;　both　methods　can　reflect　the　changes　of　the　thermal　conductivity,　and　the　thermal　conductivity　will　be　highest　if　the　initial　plasterboard　temperature　is　within　the　phase　change　temperature　interval;　the　result　of　thermal　conductivity　measured　by　unsteady　test　method　is　larger　than　that　of　steady　test　method.