The rare ginsenoside Compound K (C-K) is attracting more attention because of its good physiological activity and urgent need. There are many pathways to obtain ginsenoside C-K, including chemical and biological methods. Among these, the conversion of PPD-type ginsenosides by enzymatic hydrolysis is a trend due to its high efficiency and mild conditions. For effectively extracting from the other panaxadiol saponins, the conversion process for ginsenoside C-K was investigated using snailases in this study. The univariate experimental design and response surface methodology were used to determine the optimal hydrolysis conditions for the conversion of ginsenoside Rb1 into ginsenoside C-K by snailases. The optimum conditions were as follows: pH 5.12, temperature 51 degrees C, ratio of snailase/substrate 0.21, and reaction time 48 h. On the basis of these parameters, the addition of 1.0 mmol.L-1 ferric ion was found to significantly improve the enzymolysis of snailases for the first time. With the above conditions, the maximum conversion rate reached 89.7%, suggesting that the process can obviously increase the yield of ginsenoside C-K. The bioassay tests indicated that the ginsenoside C-K showed anti-tumor activity in a series of tumor cell lines. Based on these results, we can conclude that the process of rare ginsenoside C-K production by enzymolysis with snailase is feasible, efficient, and suitable for the industrial production and application. (C) 2018 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.