MgCl2-supported Ziegler Natta catalyst plays an important role in polyolefin industry. The solubility of MgCl2 in various alcohols has been studied to understand the mechanisms involved in the preparation of the catalyst. The solubility of anhydrous MgCl2 in methanol, ethanol, and 2-propanol and their mixtures was measured by a dynamic method at temperatures from 283.2 to 343.2 K. The solubility was found to increase with increasing temperature, but the increasing rate was dependent on the composition of solvent. In the single alcohol, the solubility value of MgCl2 is under the order of methanol > ethanol > 2-propanol at room temperature. Solubilities of MgCl2 in the mixtures of methanol + ethanol, methanol + 2-propanol, and ethanol + 2-propanol are all larger than that in the single alcohol. Three solid phases, including MgCl2 center dot 6CH(3)OH, MgCl2 center dot 6C(2)H(5)OH, and MgCl2 center dot 4(CH3)(2)CHOH, were found in the equilibrated solids by XRD characterization. The mixed -solvent model (MSE) embedded in the OLI software was applied to model the experimental solubility data. The log K-SP for the dissolution reaction of MgCl2 center dot 6CH(3)OH, MgCl2 center dot 6C(2)H(5)OH, and MgCl2 center dot 4(CH3)(2)CH OH at 298.2 K were determined to be -11.5078, -13.0943, and -10.6139, respectively.