This paper examined the use of calcined sodium silicate as a novel solid base catalyst in the transesterification of soybean oil with methanol. The calcined sodium silicate was characterized by DTA-TG, Hammett indicator method, XRD, SEM, BET, IR and FT-IR. It catalyzed the transesterification of soybean oil to biodiesel with a yield of almost 100% under the following conditions: sodium silicate of 3.0wt.%, a molar ratio of methanol/oil of 7.5:1, reaction time of 60min, reaction temperature of 60°C, and stirring rate of 250rpm. The oil containing 4.0wt.% water or 2.5wt.% FFA could also be transesterified by using this catalyst. The catalyst can be reused for at least 5cycles without loss of activity.