Abstract: Blood coagulation and platelet aggregation are crucial events in the pathogenesis of ischemic diseases,thus it can induce ischemic cardiovascular and cerebrovascular disease. Heparin has been widely used to treat anticoagulation-related diseases significantly with large side effects. The natural anticoagulant polysaccharides without heparin are discussed in this paper. Its monosaccharide compositions are mainly glucose(uronic acid),galactose(uronic acid),arabinose,mannose,xylose and rhamnose,and others. Marine polysaccharides also contains sulfuric acid,which forms sulfuric acid ester with polysaccharides. Terrestrial polysaccharides generally do not contain sulfuric acid root,but contain hexuronic acid or uric acid and other acidic components. The molecular composition and structure of polysaccharides from different sources are different,so as to its anticoagulation mechanism. The structural characteristics,anticoagulant action mechanism and related experimental methods of anticoagulant polysaccharides from Marine algae,Marine invertebrates,plants and their fruits,edible fungi and other sources are emphatically described. It is expected to provide some reference for further research and preparation of natural polysaccharides with high anticoagulant activity and low toxic side effects.