Human cytomegalovirus (HCMV) DNA EcoRI-Y fragment, which is major DNA fragment coding for 150kd phosphoprotein (pp150) of HCMV, was separated and recovered from recombinant cosmid pCM1015. The recombinant plasmids pHCY1 and pHCY2, which contain major DNA fragment coding for pp150, were constructed successfully, using the plasmid pUC19 as vector. The recombinant plasmids were analysed by restriction endonucleases and determined by Southern hybridization. The restriction sites of DNA encoding region for immunodominant epitopes of HCMV pp150 were analysed by GENEPRO system. The region could be digested by 76 kinds of restriction endonucleases. The sizes of cleaved fragments were between 4-2667 bp.