The effects of acetyl groups in dendrobium polysaccharide (DOP) on gel properties and antioxidant capacity have not been reported in the literature. In this study， we prepared DOP with different degrees of deacetylation by non-homogeneous deacetylation， analyzed its fluid properties， textural properties and total antioxidant capacity of sol and gel， and investigated the effect of acetyl group on the properties of DOP and its mechanism of action. The results showed that the presence of acetyl group made the DOP have good water solubility. With the increase of deacetylation， the viscosity of the sol decreased and the gel formation rate was faster， which changed the thermal sensitivity of the sol when forming the gel and improved the hardness and elasticity of the DOP gel significantly. In addition， the results also showed that the removal of some acetyl groups significantly improved the total antioxidant capacity. Therefore， the rheological and textural properties as well as antioxidant properties of DOP can be adjusted by controlling the amount of acetyl groups of DOP. This study may provide new ideas for the application of DOP in food， pharmaceutical and chemical industries.