〔Abstract〕 Objective To enhance the solubility expression of carbonyl reductase ChKRED20 and investigate its enzymatic properties. Methods The ChKRED20 gene was synthesized and transformed intoEscherichia coliBL21(DE3) for heterologous expression. The solubility of the protein was evaluated by adding or removing His-tag, changing its position, and adjusting the induction conditions. Further optimization was performed by varying the induction time, temperature and IPTG concentration. Subsequently, the enzymatic properties of the recombinant enzyme were examined. Results The ChKRED20 was cloned within theEscherichia colisystem to achieve soluble protein expression. This was achieved by removing the His-tag and optimizing expression conditions. Compared to enzymes with the N-terminal and C-terminal His-tags, the enzyme activity of ChKRED20 without His-tag increased by 0.77 and 1.28 times, respectively. The optimal temperature and pH for enzyme activity were 55 ℃ and 8.0, respectively. Furthermore, the enzyme demonstrated good adaptability in higher temperature and alkaline environments. Conclusion The removal of the His-tag and the optimization of expression conditions can significantly improve the soluble expression of ChKRED20 inEscherichia coli.