The invention discloses a culture medium for culturing mesenchymal stem cells. The culture medium comprises improved minimum medium IMDM, cell growth factor combination, insulin, trace elements, lipid substances, vitamin substances, hormone substances, protein molecules, amino acid substances and other compounds. The culture medium provided by the invention does not contain serum or plasma (comprising animal or human serum or plasma), thus, when the system is used for culturing the mesenchymal stem cells, zoonosis caused by the animal serum or plasma in the cell therapy process can be avoided, and the risk of human immunity reaction which is possibly caused in the cell therapy process can be avoided. The culture medium has specific chemical constituent, thus the possibility of different cultured mesenchymal stem cell properties caused by the difference of culture systems can be avoided. The culture medium is not only suitable for culturing the mesenchymal stem cells of human marrow and umbilical cord resources but also suitable for culturing the mesenchymal stem cells of other tissues or other animals, and has the advantage of wide application range.