Abstract: Objective: In this study, Tuber liyuanum was used as the experimental material to optimize and determine the extraction process of polysaccharides, and analyze the monosaccharide components. Methods: On the basis of single factor experiment, L₉(3⁴) orthogonal experiment was used to design, optimize and determine the optimum technological conditions for extracting polysaccharides by water extraction and alcohol precipitation, and the monosaccharide components of T. liyuanum were analyzed by 1-phenyl-3-methyl-5-pyridine pre-column derivatization HPLC with oxazolinone. Results: The optimum process conditions of extracting polysaccharides from T. liyuanum were as follows: Extraction temperature was 90 ℃, extraction time was 60 min, and solid-to-liquid ratio was 1:25 g/mL. Under these conditions, the yield of polysaccharides was 10.57% ± 0.31%. The polysaccharides of T. liyuanum were mainly composed of D-glucose and a small amount of D-mannose and D-galactose. And the ratio of its substances was 1:0.023:0.006. Conclusion: The water extraction and alcohol precipitation method could obtain a higher yield of T. liyuanum polysaccharides under the optimal extraction process conditions, which was simple, stable and feasible. The determination of monosaccharides composition in T. liyuanum polysaccharides by pre-column derivatization HPLC was simple, reproducible and accurate, which could provide a theoretical basis for further research on T. liyuanum polysaccharides in pear orchards.