Abstract: Objective: To isolate and purify polysaccharides from Dendrobium officinale, characterize their structure and explore their anti-inflammatory effects. Methods: Polysaccharides from Dendrobium officinale were obtained by water extraction and alcohol precipitation. DOP-1 was purified by DEAE-52 cellulose ion exchange resin and Sephadex G-100. Ultraviolet scanning, GC, high-performance gel chromatography, infrared spectroscopy and nuclear magnetic resonance scanning were used to analyze the structure of DOP-1 polysaccharide, and the inhibitory effect of DOP-1 on the proliferation of RAW 264.7 cells was determined. And its effect on the expression of NO, TNF-α and IL-1β in RAW264.7 cells induced by LPS. Results: DOP-1 was a homogeneous polysaccharide composed of rhamnose, mannose, glucose and galactose with a monosaccharide molar ratio of 0.6:9.0:2.7:2.9 and a molecular weight of 59.2 kDa. DOP-1 did not significantly inhibit the proliferation of RAW 264.7 cells. Compared with the model group, DOP-1 significantly inhibited the expression of NO, TNF-α and IL-1β. Conclusions: The polysaccharides of Dendrobium officinaleobtained in this study had clear structure and good anti-inflammatory activity, and the extraction conditions were feasible. This study would provide theoretical basis for the development and utilization of polysaccharides of Dendrobium officinale with anti-inflammatory effect.