Objective: To establish total saponins from Panax japonicas (SPJ) activity related to quality standards by the quantification of main active ingredient. Method: The extraction process of total saponins from P. japonicas (SPJ) was optimized to obtain total saponin extraction. HPLC was used to determine the content of the main ingredients in the standard extract. The main ingredients were made into the preparations of principal component cluster equal with total saponins of herbal extracts to evaluate the differences between the principal component cluster and the active ingredients of herbal extraction through vitro antioxidant model. Result: Vitro antioxidant activity of standard extracts was 71.30 U·g-1; the content of saponin V of P. japonicus was 24.9 mg·g-1; saponin Ⅳa was 90.6 mg·g-1; saponin Ⅳ was 38.7 mg·g-1; Pjs-2 was 41.1 mg·g-1. Vitro antioxidant activity of the principal component cluster is 64.79 U·g-1. Conclusion: The method taking saponin V

saponin Ⅳa

saponin Ⅳ and Pjs-2 from P. japonicus as the principal component of the Panax japonicus total saponins has a high accuracy

which is scientific and reasonable. In the samples of Panax japonicus total saponins

the content of saponin V is no less than 24.9 mg·g-1

saponin Ⅳa is no less than 90.6 mg·g-1

saponin Ⅳ is no less than 38.7 mg·g-1

Pjs-2 is no less than 39.6 mg·g-1.