In order to find a method suitable for purifying large amount of CD34(+) cells, from 5 cases who accepted autologous peripheral blood stem cell transplantation, CD34(+) cells were collected and enriched by using Isolex 300i (Nexell). Phenotypes were detected by flow cytometry and the biological viability were assayed by the colony-forming experiments and cell expansion experiment in vitro. The results showed that the number of mononuclear cells first collected was about (3.5 - 6.0) x 10(10) and (0.55 - 1.2)% of cells were CD34 positive. The number of positive production was about (2.0 - 3.0) x 10(8); the CD34(+) cells purity was (75 - 85)% and the yield was (40 - 65)%. The CD34(+) cells of positive production could expand up to 2 - 3 times when cultured with SCF + IL3 + FL + TPO + EPO in vitro. The results of colony-forming experiments demonstrated that the CD34(+) cells collected has enough colony-forming ability. All results showed the enriched CD34(+) cells with biological viability. In conclusion, the CD34(+) immunomagnetic isolation apparatus Isolex300i is suitable to clinical application for a large amount of CD34(+) cell enrichment.