The invention discloses a modified tamarind gum polymer as well as a preparation method and an application thereof. The modified tamarind gum polymer is prepared from raw materials in parts by mass asfollows: 20-35 parts of tamarind gum, 0.5-4 parts of isocyanatoethyl methacrylate, 0.5-4 parts of a maleimide monomer, 0.2-0.8 parts of an initiating agent and 50-65 part of demineralized water. Whenused as a dry and wet rubbing fastness enhancer, the modified tamarind gum polymer has the advantages that the modified tamarind gum polymer has high color fastness, dry and wet fastness and color fastness to demineralized water washing can be improved, the effect on sensitive color light is little, dosage is less and the like.