Objective: To optimize preparation technology of phosphorylated polysaccharides from Dimocarpus longan. Method: Phosphorylation reaction was used to prepare phosphorylated polysaccharides from D.longan by using POCl3

with degree of substitution as index

which was determined by phosphomolybdate blue method

a Box-Behnken central composite design of response surface methodology design and single factor test were used to investigate three factors influencing preparation technology

such as volume ratio of pyridine-POCl3

reaction temperature and time. Result: Optimum preparation technology was as following:volume ratio of pyridine-POCl3 3:1

reaction temperature 0 ℃

reaction time 60 minutes

a higher degree of substitution of 0.018 4 was obtained. Conclusion: This optimized preparation technology was stable and feasible

it could be extended to application in industrial production.