Objective: To optimize purification technology of total polysaccharides from Liuwei Dihuang biological preparation. Method: With the amount of crude polysaccharides as index

orthogonal test was adopted to optimize alcohol precipitation process.Based on single factor tests

taking composite score of deproteinization rate and retention rate of total polysaccharides as index

orthogonal test was adopted to optimize deproteinization process.With composite score of decolorization rate and retention rate of total polysaccharides as index

orthogonal test was adopted to optimize decolorization process. Result: Optimum alcohol precipitation process was as follows:alcohol precipitation concentration of 85%

alcohol sedimentation time for 6 h

relative density of solution concentration of 1.05.Optimum deproteinization process were as follows:volume ratio of total polysaccharide solution to trichloroacetic acid (TCA) of 1: 2

volume ratio of TCA-butanol of 1: 15

vibration time of 20 min

standing for 0.5 h.Optimum decolorization process was as following:decolorization temperature of 40 ℃

the amount of activated carbon 6%

decolorization time of 40 min.Quality of crude polysaccharides was 8.92 mg

deproteinization rate was 80.23%

decolorization rate was 74.84%

retention rate of total polysaccharides was 78.69%. Conclusion: These optimized extraction processes are stable and feasible

which are suitable for development of health products of total polysaccharides from Liuwei Dihuang biological preparation.