Abstract: In order to improve the leaching and carbonation rates of calcium and magnesium ions in steelmaking slag,the chemical and phase compositions were analyzed by fluorescence spectrometry and X-ray diffraction(XRD). The leaching effect of different amounts of hydrochloric acid and acetic acid and the influence of temperature and stirring conditions on the leaching rate were investigated in detail. Hydrochloric acid as a leaching reagent can achieve a better leaching result and its leaching rate is up to 93.4%,higher than 85.8% for acetic acid; moreover,the purity of calcium carbonate is 91.02% and the conversion rate is 56.5%. The leaching rate with acetic acid is higher than that with hydrochloric acid at 80℃. Stirring is favorable for calcium and magnesium ion leaching.