Insulin-like growth factor-1 (IGF-1) has become a particularly attractive therapeutic target because of its role in various physiological processes, including the regulation of cellular proliferation. However, high-level expression and purification of recombinant IGF-1 (rIGF-1) in Escherichia coli (E. coli) is hindered by its incorporation into inclusion bodies in the bacteria. To overcome this problem, IGF-1 was fused to small ubiquitin-related modifier (SUMO) and subsequently transformed into E. coli Rosetta (DE3). After induction with 0.5 mM isopropyl-1- thio-β-galactopyranoside for 4 h at 37℃, SUMO-IGF-1 concentration reached 26.2% of the total protein. We then purified the fusion protein with affinity chromatography and used SUMO protease to release rIGF-1 from the column. The purity of rIGF-1 was shown by high performance liquid chromatography to be greater than 95%. Mitogenic activity assays showed that the purified rIGF-1 stimulated the proliferation of NIH-3T3 cells in a dose-dependent manner. These findings demonstrate that fusion of SUMO to IGF-1 enhances its solubility and purification. In conclusion, we acquired sufficient, soluble expression, bioactive of rIFG-1 in E.coli, which can then be used for clinical applications.