In this study,Morchella esculenta polysaccharide(ME-P) were extracted by hot water extraction from wild M. esculenta in Xiaojin County,Sichuan Province.Fourier transform infrared spectroscopy (FT-IR),high performance liquid chromatography (HPLC),gas chromatography mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) were used to identify the structure of ME-P.CCK-8 method was used to detect the drug toxicity of ME-P and to explore the antitumor activity of ME-P in vitro.The results showed that ME-P contained pyranose ring,and the monosaccharides were composed of mannose,glucose and galactose with a ratio of 4∶4∶1.The polysaccharides are characterized by a novel structure,which is characterized by the alternating linkage of 1,2,3,4,6-D-mannose and 2,3,4,6-D-mannose as the main chain,1,6-D-glucose and 1,2,6-D-galactose as the branch chain,and the connection of 4-D-glucose and 1,2,6-D-galactose as a repeating unit of terminal monosaccharide.ME-P is non-toxic to macrophages (RAW 264.7) and has a very significant effect (P<0.01) on proliferation.The proliferation rate of RAW 264.7 can be as high as 79.5% at a mass concentration of 1.25 μg/mL.At the same time,it had inhibitory effect on mouse colon cancer cells (CT26.WT) and gastric cancer cells (MFC),and the inhibition effect was better at low concentration.When ME-P was 1.25 μg/mL,the inhibition rates of ME-P on CT26.WT and MFC were 28.20% and 34.23%,respectively.This study shows that M. esculenta polysaccharides (ME-P) in Xiaojin County,Sichuan Province is a novel polysaccharide composed of mannose,glucose and galactose,which is non-toxic and has significant inhibitory effect on tumor cells.The results provide a scientific basis for the development and application of Morchella polysaccharides.