Although carbonation sequestration with calcium-based residues can achieve in-situ fixation and permanent storage of CO2，the process barriers are harsh reaction condition and slow reaction rate.In this paper leaching characteristics of Ca2+ from residues and its carbonation were tested in an ultrasonic-assisted reactor，and compared with those obtained under stirring condition.Effect of different process parameters for leaching，and change of pH and conductivity for carbonation reaction was measured and analyzed.The products from carbonation were characterized by XRD，SEM and TGA techniques.The results show that the leaching of Ca2+ from calcium-based residues can be effectively promoted by ultrasonic-assisted，which increases with enlargement of ultrasonic power and depends on type of residue，leaching time，pH of leaching solution，slurry volume as well as particle size of residue.The Ca content，leaching efficiency and ultrasonic-assisted effect are higher for steel slag and carbide slag than for other residues.The Ca2+ concentration in leaching liquor increases with enlargement of ultrasonic power and decrease of pH.The ultrasonic enhancement effect is more obvious for bigger residue particles.Compared with mechanical stirring，not only leaching process but also carbonation reaction can be strengthened by ultrasonic-assisted.