It is more reliable to trace the origin of the truncated pyramidal ceiling in architecture since it is a kind of architectural form. The flat top part of the truncated pyramidal ceiling confines its use and popularity in house construction. However,it enjoyed a special position in burial buildings. It was particularly after the rockcut tombs appeared that this ceiling structure dominated the tomb ceilings by virtue of its bright and spacious form. This tradition was followed in the tombs of the Western Jin,Eastern Jin,and Sixteen Kingdom Period in Hexi regions,where the technology for constructing cave tombs from the conglomerate rock was available. This construction technology and experience were inevitably borrowed into cave construction. Therefore the truncated pyramidal ceiling was sure to have grown out of local tomb construction.