Objective：To prepare NIH3T3 cells harboring microencapsulated VEGF gene and investigate the proliferation,activity and metabolic function of the modified cells.Methods: Microencapsulated VEGF modified NIH3T3 cells were prepared through an alginate-BaCl2 process.Morphological appearance of the microencapsulation and the cell morphology were observed under inverted phase microscope; untreated NIH3T3 cells served as control.The concentrations of VEGF in the culture supernatant (collected every 48 hours) were measured by ELISA; the proliferation and vitality of the cells were examined by MTT assay and flow cytometry with PI staining.Results: The microcapsules were round in shape and the cells grew well.There was no significant difference in the concentrations of VEGF，MTT values and vitalities of cells between the 2 groups.Conclusion: The growth and metabolic functions of NIH3T3 cells are not influenced by microencapsulated NIH3T3 cells harboring VEGF gene.The bio-properties of modified cells are similar to those of the control cells,which lays a foundation for transplantation of microencapsulated VEGF modified NIH3T3 cells in vivo.