Histidine-polyaspartic acid (His-PASP), an effective antiscaling inhibitor, was synthesized by polysuccinimide (PSI) and histidine. His-PASP exhibited a promising antiscaling property by inhibiting the reaction crystallization of Ca-scale crystals. The crystal form and surface morphology of Ca-scale crystals were changed after the addition of His-PASP. The hard scale was turned into soft dirt and can be easily washed away. The binding between His-PASP and calcite was exothermic and the energy was higher than the traditional adsorption energy. His-PASP possessed a favorable anticorrosion efficiency for carbon steel in cooling water. In the test of dispersing Fe2O3, the transmittance of the supernatant was reduced with increasing His-PASP dosage.