Glycerol carbonate was synthesized by glycerol and dimethyl carbonate with CaO as catalyst. The effects of reaction temperature, reflux temperature, reactant molar ratio, catalyst dosage, and time on the reaction were studied by orthogonal experiment and single-factor test. The optimal reaction conditions were obtained as follows: reaction temperature 75 ℃, reflux temperature 60 ℃, n(dimethyl carbonate): n(glycerin) = 2.5:1, catalyst dosage = 0.8%, reaction time = 2 h；the conversion of glycerol and the yield of glycerol carbonate reached 97.89% and 96.78%, respectively. Finally, The storage stability and reusability of CaO were also evaluated, indicating that although CaO was of relatively good storage stability, its reusability was so poor that it lost its activity after the first cycle of use.