Background:　Human　umbilical　cord　mesenchymal　stem　cells　with　capabilities　for　self-renewal　and　multi-differentiation　have　attracted　widespread　attention.　Objective:　To　develop　an　efficient　method　for　isolation　and　culture　of　human　umbilical　cord　mesenchymal　stem　cells,　and　to　analyze　the　cell　biological　features.　Methods:　Mesenchymal　stem　cells　were　isolated　and　cultured　from　human　umbilical　cord　by　improved　tissue　cultivation.　Immunophenotype　and　cell　cycle　were　analyzed　by　flow　cytometry.　Growth　curve　was　determined　by　MTT　assay,　and　differentiation　ability　was　evaluated　by　in　vitro　osteogenic　and　adipogenic　induction　as　well.　Results　and　Conclusion:　Some　fusiform　cells　crawled　out　from　human　umbilical　cord　tissues　after　cultivation　for　5　days　and　formed　colonies　about　10　days　later.　When　the　removed　tissues　were　further　cultured,　more　cells　appeared　again　within　2　days　and　formed　colonies　after　5　days.　The　isolated　cells　exhibited　similar　morphology　of　fibroblast-like　shape　after　passage.　Furthermore,　the　cells　expressed　CD90,　CD105,　but　were　negative　for　the　markers　of　CD34,　CD45,　HLA-DR.　Population　doubling　time　of　the　cells　calculated　from　the　result　of　MTT　was　about　50　hours　and　cell　cycle　analysis　showed　that　41.24%　cells　were　in　the　G2/S　phrase.　Therefore,　the　isolated　cells　had　a　high　prolification　ability.　In　addition,　the　isolated　cells　could　be　induced　into　osteoblasts　and　adipocytes　in　vitro.　In　a　word,　the　results　of　this　study　demonstrated　that　the　cells　from　the　second　tissues　culture　possessed　the　biological　characteristics　of　mesenchymal　stem　cells　and　more　primary　umbilical　cord　mesenchymal　stem　cells　were　acquired　through　the　improved　method.