Transferring beta-globin gene and its enhancer into human hematopoietic cells is the basis for applying beta-thalassemia gene therapy in clinical practice. We isolated ecotropic virus producing clones and amphotropic virus producing clones by using a replication-defective retrovirus vector containing beta-globin gene and its enhancer to transfect ecotropic packaging cell line phi-2 and amphotropic packaging cell line PA317. Then by ping-ponging supernatant infection between ecotropic producer clone and amphotropic producer clone, we obtained high titer amphotropic PA317 producer clones with the highest titer up to 5.9 x 10(6) CFU/ml. Human mononuclear bone marrow cells were infected repeatly with this high titer virus vector under stimulation of hematopoietic growth factors IL-3, IL-6 and SCF, Southern blot hybridization analysis showed that beta-globin gene and its enhancer had been integrated into the genome of human hematopoietic cells.