The invention relates to a method for removing sodium chloride from cassava starch polysaccharide-iron complex liquid. The method comprises the following steps: A, adding cassava starch and water intoa reaction kettle, heating and regulating pH value, adding hydrogen peroxide solution to degrade the cassava starch, so as to obtain oligosaccharide solution with the weight-average molecular weightof 3-27KDa, then adding ferric trichloride solution and alkali, and carrying out complex reaction, so that cassava starch polysaccharide iron liquid is obtained; B, carrying out ultrafiltration on thecassava starch polysaccharide iron liquid obtained in the step A, and intercepting micromolecular cassava starch polysaccharide iron complex with the molecular weight of 2.5-200KDa to remove part ofsodium chloride; C, carrying out nanofiltration on permeate liquid obtained in the step B, and intercepting micromolecular cassava starch polysaccharide iron complex with the molecular weight of 200 Da by virtue of a nanofiltration membrane to remove sodium chloride; and D, mixing interception liquids obtained in the steps B and C, and carrying out spray drying, so that solid cassava starch polysaccharide iron complex is obtained, and nanofiltration permeate liquid can be directly discharged. The method provided by the invention has the advantages that technology is simple, energy conservationand environmental protection are realized, conditions are mild, and continuous production can be easily realized; concentration of sodium chloride in the cassava starch polysaccharide-iron complex liquid can be lowered; and recovery rate of the cassava starch polysaccharide iron complex is higher than 99%; and removal rate of sodium chloride is higher than 98%.