Sucrose phosphorylase and glucan phosphorylase were chosen to synthesize the amylodextrin and the process conditions were optimized in this paper.Using sucrose as substrate and phosphate as buffer,the reaction was catalyzed by sucrose phosphorylase to produce the intermediate product glucose-1-phosphate which was determined by liquid chromatography-mass spectrometry.Based on the above system,the synthetic reaction using maltotetraose as primer was catalyzed by glucan phosphorylase to produce amylodextrin.The degree of polymerization of the product contained in the system was determined by high-performance anion-exchange chromatography.The optimal conditions including enzyme concentration,time,pH and temperature were determined by mono-factor experiment.The results indicated that the optimum conditions of the reaction which using sucrose phosphorylase as catalyst to produce glucose-1-phosphate were as follows: enzyme concentration 4.0 U/mL,reaction time 4 h,pH 6.5,temperature 40℃;and conditions of reaction which using glucan phosphorylase as catalyst to synthesis amylodextrin were as follows: enzyme concentration 5.0 U/mL,reaction time 4 h,pH 4.5,temperature 40℃.