Polyaspartic acid (PASP) composite material, a scale and corrosion inhibitor, is prepared from PASP, acrylic acid-acrylic ester- itaconic acid tripolymer (IA-AA-AE) and 2-phosphonobutane- 1,2,4-tricarboxylic acid (PBTCA). The scale inhibition effects of PASP and PASP composite are investigated. Calcium carbonate crystals in scale samples are characterized by means of SEM. Experimental results show that the scale inhibition rate can reach 98.7 % and corrosion inhibition rate 96.5 % under the conditions of Ca2+ 639 mg.L-1 and PASP composite material 40 mg.L-1. SEM results show that calcite and aragonite can be transformed into vaterite completely by using PASP composite material.