Abstract: Influences of vacuum freeze-drying on the active constituent of Panax notogiseng ( P. notoginseng) and the optimal drying process with the content of Panax notoginseng Saponins (PNS) and Dencichine were investigated. The single factor experiment was utilized combining with response surface methodology and satisfaction function to optimize the drying process of P. notoginseng. On the basis of single factor experiments, different optimum conditions including clapboard temperature and vacuum pressure were selected, and the method of response surface analysis was adopted according to the central composite design (CCD) experimental design principles. In addition, the P. notoginseng quality was evaluated by scanning electron microscope (SEM). The optimum drying conditions of the P. notoginseng are as follows: vacuum pressure of 56.9 Pa, the clapboard temperature of 45.2 ℃. Under the optimal drying conditions, the mass content of PNS and Dencichine could reach 9.77% and 1.76%, respectively. The satisfaction function results showed that the maximum value of the optimum process conditions was 4.353, and the values of three parallel experiments are similar to the optimum model. This technology could be used to guide industrial production of P. notoginseng and provide a theoretic basis.