This paper discusses the synthesis of biodiesel catalyzed by solid base of K(2)CO(3)/HT using Jatropha curcas oil as feedstock. Mg-Al hydrotalcite was prepared using co-precipitation methods, in which the molar ratio of Mg to Al was 3:1. After calcined at 600 degrees C for 3 h, the Mg-Al hydrotalcite and K(2)CO(3) were ground and mixed according to certain mass ratios, in which some water was added. The mixture was dried at 65 degrees C, and after that it was calcined at 600 degrees C for 3 h. Then, this Mg-Al hydrotalcite loaded with potassium carbonate was obtained and used as catalyst in the experiments. Analyses of XRD and SEM characterizations for catalyst showed the metal oxides formed in the process of calcination brought about excellent catalysis effect. In order to achieve the optimal technical reaction condition, five impact factors were also investigated in the experiments, which were mass ratio, molar ratio, reaction temperature, catalyst amount and reaction time. Under the best condition, the biodiesel yield could reach up to 96%.