Abstract: A new saponin named yixinoside A and three known compouns were isolated from the aerial part of Gymostemma yixingense CY Wu et SK Chen, By means of chemical evidences and spectral analysis (IR, FAB-Ms,¹H-NMR,¹³C-NMR),the structure of yixinoside A was established as 1β,3β,12β,20(S)-tetrahydroxy-dammar-24( 25 )-en-3-O-β-D-glucopyranosyl(1-2)-β-D-glucopyranoside-20-O-α-L-rhamnopyranosyl(1-6)-β-glucopyranoside.The known compounds were identified as gypenoside XLIV,XLII and ginsenoside Rb1.In addition, a new aglycone 1β-hydroxylpanaxadiol and a new secondary saponin named yixinoside B were obtained by hydrolysis of yixinoside A. This paper report mainly structural determination of yixinoside A.