The　equivalent　thermal　conductivities　of　50　kinds　of　hollow　clay　bricks　with　the　size　of　240　×　115　×　90　(in　mm)　and　different　hole　number　and　arrangement　have　been　predicted　numerically　by　the　finite　volume　method.　The　influences　of　the　hole　surface　radiation　and　the　indoor-outdoor　temperature　difference　are　also　considered.　The　results　reveal　that　the　hole　surface　radiation　can　not　be　neglected.　The　hole　number　and　arrangement　have　significant　effects　on　the　equivalent　thermal　conductivity.　There　is　an　optimal　configuration　for　which　the　equivalent　thermal　conductivity　is　the　lowest.　For　this　optimum　configuration　its　equivalent　thermal　conductivity　does　not　vary　with　the　indoor-outdoor　temperature　difference.　The　simulation　results　provide　valuable　data　for　the　hollow　brick　design　in　the　building　engineering.