The invention discloses a panax notoginseng polysaccharide extract and a preparation method, preparations and applications thereof. The panax notoginseng polysaccharide extract is prepared by taking waste residues produced after panax notoginseng saponins are extracted as raw materials through the steps of extraction, concentration, purification, drying, crushing and detection, wherein the content of panax notoginseng polysaccharides is not less than 15%. The preparation method of the panax notoginseng polysaccharide extract comprises the steps of extraction, concentration, purification, drying, crushing and detection, and specifically comprises the steps of adding waste residues produced after panax notoginseng saponins are extracted into purified water for extracting, carrying out filtration and concentration on the obtained object, adding ethanol into the obtained object for precipitating, and carrying out filtration, purification and drying on the obtained product so as to obtain a target dried product. Pharmaceutical excipients are added into the panax notoginseng polysaccharide extract to be prepared into powder, capsules, granules, tablets or pills; and the panax notoginseng polysaccharide extract is applied to the preparation of antineoplastic drugs and immunity enhancing drugs. According to the invention, waste residues produced after panax notoginseng saponins are extracted are reused, thereby changing waste material into things of value, facilitating the comprehensive utilization of panax notoginseng resources, reducing the cost and improving the economic benefits.