The　phase　change　material　(PCM)　layer　used　for　energy　storage　of　the　wall　in　winter　can　absorb　a　mass　of　heat　from　the　solar　radiation　in　daylight　and　release　the　heat　at　night,　thus　reduce　the　air-conditioning　energy　consumption　and　maintain　the　indoor　air　temperature.　To　study　thermal　performance　of　the　PCM　wall　and　optimize　the　application　of　PCMs,　a　thermal　performance　testing　equipment　was　designed　and　the　case　that　solar　light　suddenly　irradiated　the　PCM　layer　in　daylight　and　disappeared　at　night　in　an　air-conditioning　room　was　experimental　and　numerical　simulated.　Results　show　that　PCM　layers　can　change　the　absorptivity　of　the　wall,　and　then　improve　surface　temperature　and　heat　flux　in　heat　storage　process.　The　addition　of　the　PCM　to　the　wall　can　enhance　the　heat　storage　in　the　wall.　Besides,　the　wall　surface　temperature　in　heat　release　process　was　improved.　To　make　the　heat　released　constantly　in　a　long　time　at　night,　the　PCM　with　proper　phase　change　temperature,　narrow　phase　change　range　and　large　latent　heat　should　be　chosen.　The　effect　of　the　specific　heat　capacity　and　the　heat　conductivity　is　unobvious.　Using　the　proper　PCM,　heat　release　time　can　be　10.3　h.　It　is　unnecessary　to　make　the　radiation　time　too　long.　Two　hours　radiation　time　is　enough　for　the　PCM　used　in　the　experiment　to　store　the　solar　heat.　(C)　2018　Elsevier　Ltd.　All　rights　reserved.