Myrrha, the gum resin exudate from Commiphora myrrha (Nees) Engl. tree, has been extensively used in traditional medicine for their beneficial effects. In this work, we isolated and purified water-soluble polysaccharide fraction (WSP), which afforded a yield of 42%. The chemical composition of WSP was mainly consisted of 83.33±2.63% carbohydrates, among them 79.25±1.06% are neutral monosaccharides and 13.4± 2.18% proteins, with traces of polyphenols (3.82%): The majority components of monosaccharides were galactose (45%) and arabinose (44%), with low levels of xylose (6%), and mannose (5%): In order to evaluate the immunostimulatory effect of WSP, phagocytic activity of opsonized human leucocytes against opportunist pathogen yeast, Candida albicans, was assessed. WSP could significantly (p < 0.05) enhance phagocytic capacity at the dose of 150 μg/ml, which showed a phagocytic activity of 29%. Moreover, the antihyperglycemic activity of extract was determined by α-D-glucosidase inhibitory activity, in vitro. WSP displays a promising inhibitory activity with an IC50 value of 8.30±0.12 mg/mL. The results of this work provide new knowledge in the field of chemical composition and biological activities of polysaccharides of Commiphora myrrha gum and might play an important role in activating phagocytosis leucocytes cells, thus having contribution to antidiabetic activity.