Abstract: The composition analysis and antioxidant activity of Cistanche lanzhouensis polysaccharides were studied. A fresh sample of the fleshy stem of the desert plant Cistanche lanzhouensis was used to extract the crude polysaccharide (CLP) of Cistanchelanzhouensis by the traditional water extraction and alcohol precipitation method, and the crude polysaccharide CLP was eluted by the DEAE-cellulose anion exchange chromatography column method to obtain neutrality Sugar CLP-1 and acid sugar CLP-2. The molecular weight and monosaccharide composition were determined by high performance gel permeation chromatography (HPGPC) and high performance liquid chromatography (HPLC), and the antioxidant activity was determined by DPPH free radical scavenging experiment and total antioxidant capacity experiment. According to the measurement of molecular weight by HPGPC, it was concluded that Cistanche lanzhouensis polysaccharides had multiple elution peaks, and its polysaccharides molecular weight was mainly distributed between 0~10 kDa, which was a heterogeneous polymer hetero polysaccharide; the neutral sugars CLP-1 and the monosaccharide composition of the acid sugar CLP-2 was significantly different. The more obvious monosaccharides and their proportions in CLP-1 were: mannose 2.78%, galacturonic acid 4.07%, glucose 88.62%, galactose 1.80% and arabinose 2.39%; CLP-2 were: rhamnose 5.79%, galacturonic acid 7.78%, glucose 9.99% and galactose 13.30%. According to the results of antioxidant experiments, CLP-1 had the best antioxidant effect. The scavenging ability of DPPH free radicals at a concentration of 2.0 mg/mL was as high as 91.73%, and the IC₅₀ was 0.383 mg/mL, and the total antioxidant capacity at the same concentration was higher than CLP and CLP-2. In this paper, a preliminary analysis of the polysaccharides of Cistanche lanzhouensis is carried out to provide basic data support for the further research of Cistanche lanzhouensis.er research of Cistanche lanzhouensis.