Provided is a new type serum-free medium. The medium comprises: DMEM with high glucose (the content of glucose being 4.5 g/L), B27, recombinant human basic fibrolast growth factor (b-FGF), nicotinamide, N-2, vinblastine III (conophylline), non-essential amino acid (NEAA), heparin, epidermal growth factor (EGF), hepatocyte growth factor (HGF), a serum replacement (SR), an insulin-transferrin-selenium complex (ITS), and pentagastrin. Inducing differentiation of mesenchymal stem cells into insulin-secretion-like cells can be achieved in six days in one step using the medium.