Objective To construct lentiviral vectors containing peptide P1-GFP fusion genes.Umbilical cord derived mesenchymal stem cells were infected with lentivirus carrying peptide P1 and GFP fusion genes.To inject the targeted umbilical cord derived mesenchymal stem cells into mice and to detect GFP expression in the spleen.Methods Umbilical cord derived mesenchymal stem cells were cultured with adhered tissues of umbilical cord smaller than 1 mm3 . Lentiviral vector containing P1-GFP fusion genes with engineering technology was constructed and infected the umbilical cord derive mesenchymal stem cells.Targeted umbilical cord derived mesenchymal stem cells were intravenously injected in the mouse tail vein and after 18 hours GFP expression was detected with immunohistochamical staining of the spleen tissues.Results Harvested umbilical cord derived mesenchymal stem cells grew well in culture medium. Green fluorescence on umbilical cord derived mesenchymal stem cells were observed under fluorescence microscope at 18 hours after infected with lentivirus.Green fluorescence intensity of umbilical cord derived mesenchymal stem cells was increasing over time and reached a peak at 72 hours.Umbilical cord derived mesenchymal stem cells highly expressed CD105 (90.0%)/CD44 (98%) and CD73 (85.0%)/CD90 (98.5%) molecules.GFP expression was detected in the spleen after intravenous injection of targeted umbilical cord derived mesenchymal stem cells in the mice 18 hours later.GFP expressing cells intimately contacted with lymphocytes.Conclusions Targeted umbilical cord derived mesenchymal stem cells contain P1-GFP fusion genes are constructed.Targeted umbilical cord derived mesenchymal stem cells can be targeted to mouse spleen and intimately contact with lymphocytes after intravenous injection.Our results lay the groundwork for further studies.