Glycidyl methacrylate(GMA)was synthesized through two steps．Firstly，Sodium methacrylate was prepared from methyl acrylic acid and NaOH ，which was ground and dried．With different inhibitors and phase transfer catalysts，GMA was gained by the reaction of Sodium methacrylate and Epichlorohydrin(ECH)with a certain percentage in a dry reaction system and distilled through vacuum distillation．The results show that hydroquinone is the best inhibitor，and phase transfer catalyst is tetra—butylammonium bromide(TBAB)．The optimum reaction conditions are obtained by the orthogonal experimental design：the reaction temperature is 90-95。C．the reaction time is 4 h， (sodium methacrylate)： (ECH)=1：6．Under the given conditions the yield of products can reach 86．5%with purity of98．6% ．