Objective: To analyze color difference of Polygoni Multiflori Radix with different processing method and processing degree combined with traditional traits

and supply a research basis for color data standard of this herb. Method: Traits of processed products of Polygoni Multiflori Radix were observed

CM-5 colorimeter was adopted to measure L

a

b values of samples

E (total color value) and ΔE (color difference) were calculated.Cluster analysis and SAS 9.2 statistical software were employed to analyze the correlation between samples with different processing degree and the test result. Result: Color of the raw products from 2 origins and the control pieces powder of raw products was yellowish-white

the E was 70.31±3.The color of control pieces powder of Polygoni Multiflori Radix Praeparata was chocolate brown

the E was 52.24

compared with control pieces powder of raw products

the ΔE was 18.63.The color of Polygoni Multiflori Radix deepen after processing

and E decreased

variation laws of the 4 processing methods were the same.With the processing time extended

the color of samples gradually from claybank

light brown

dark brown

chocolate brown and until became brownish-black

the E gradually reduced from 61.11 to 30.45

E could indicate processing degree of Polygoni Multiflori Radix.It can distinguish the raw products and processed products by cluster analysis. Conclusion: Colorimeter tests can distinguish the raw products and processed products of Polygoni Multiflori Radix

and it can objectively and accurately express powder color change of Polygoni Multiflori Radix Praeparata with different processing degree.