OBJECTIVE To optimize the induction condition of human NOR1 gene expression in E.coli. and purify NOR1 recombinant proteins. METHODS A full-length cDNA of human NOR1 was inserted into the corresponding region of pET28b expression vector to yield recombinant prokaryotic expression vector pET28b-NOR1. The prokaryotic expression vector pET28b-NOR1 was introduced into the bacterial host E.coli Rosettablue(DE3). Recombinant NOR1 protein was induced at different conditions. Induction condition was optimized to obtain high yield of recombinant protein. At last, the recombinant NOR1 protein was purified by Ni-IDE chromatography resin. RESULTS Recombinant NOR1 protein was induced by IPTG in a dose-dependent manner. Increase of kanamycin concentration and induction temperature resulted in high yield of recombinant protein. The most recombinant protein was found in inclusion bodies. The recombinant His-NOR1 protein was purified with Ni-IDE chromatography resin under denature condition. CONCLUSION IPTG, kanamycin concentration and temperature can affect the expression of recombinant NOR1 protein in pET28b system. High yield of recombinant NOR1 protein is achieved by inducing 1 mmol/L IPTG and 200 μg/mL kanamycin at 37 degree. Recombinant His-NOR1 protein with high purity is purified.