Objective: To study the changes of low molecular weight saccharide in Rhizoma Polygonation during processing. Method: HPLC analysis was performed on a BIO-RAD Aminex HPX-87C column (7.8 mm×300 mm

9 μm)

and the mobile phase was water. The flow rate was 0.4 mL·min-1 and the temperature of the ELSD was 105 ℃. Result: Sucrose and fructose were detected in the three species of Rhizoma Polygonation raw products but not glucose

and which was detected after processed to 8 h or 16 h on the species; the total contents of reducing sugar and low molecular weight saccharide were the highest when processed to 16 h which were 4-27 times higher than those of the raw products. Conclusion: The composition and the contents of low molecular weight saccharide in three species of Rhizoma Polygonation varied during processing.