Astragalus polysaccharides extracted from traditional chinese medicine Astragalus membranaceus, exhibits multiple biological activities, including antitumor, immunomodulation, antioxidant, hypoglycemic effect. Specially, its anti-tumor effect has attracted much attention in recent years. Here we review the antitumor functions and mechanisms of astragalus polysaccharides by reading the current papers at home and abroad in order to provide reference for the future research and application. Its antitumor effect is elucidated from several perspectives: mediating tumor immune, inhibiting proliferation, migration and invasion of tumor cell, inducing apoptosis, anti-angiogensis and anti-lymphangiogenesis, as well as chemotherapy drugs’ synergy and attenuation.