Abstract:The optimum extraction conditions and stability of pigment in the rhizome of Smilax china L.were studied.The results of single factor experiment were used as the experimental basis and the absorbance was taken as the detection index.The optimum conditions for extracting the root and stem pigments of Smilax china L.were optimized by orthogonal design of L9（33）.The effects of oxidation and reduction，metal ion and other factors on the stability of Smilax china L.rhizome pigment were investigated.The results showed that the optimum extraction conditions were as follows：extraction temperature 70 ℃，concentration of 50 % ethanol，extraction time 1.5 h，ratio of material to liquid 1 ∶10（g/mL）.The results of stability test showed that adding different volume fraction of oxidizing agent H2O2 and different concentration of reducing agent Na2SO3 had an increasing trend of the absorbance on the rhizome pigment of Smilax China L.Fe3+had significant influence on the pigment when metal ion was detected and the influence of other metal ions on the pigment of Smilax china L.rhizome was not obvious.