Abstract: This paper used potato pulp which was the main by-products during potato starch processing as raw material for preparing microcrystalline cellulose. First,sodium hydroxide was used to remove hemicellulose,then acid sodium chlorite was used to remove lignin,finally dilute hydrochloric acid was used to remove residual starch,and hydrolyze cellulose to microcrystalline cellulose(MCC). Compared with traditional methods,preparation of microcrystalline cellulose by one-step acid hydrolysis could omit the step of preparation of crude fiberand pre-processing to removing starch by acid hydrolysis. By simplify the preparation process of potato pulp MCC,production and utilization efficiency could be enhanced. The optimal condition which was explored through single factors and orthogonal experiments was as follows:hydrochloric acid concentration of10%,acid hydrolysis time of 120 min,acid hydrolysis temperature of 95℃,solid-liquid ratio of 1∶2.