Effects of calcium chloride, calcium oxide, sulfate sodium and carbonate sodium on thaumasite formation were investigated by synthesizing thaumasite through Struble method. Precipitates at different ages of thaumasite formation reaction were characterized by FTIR and XRD. It is indicated that both calcium chloride and calcium oxide can increase the rate of thaumasite formation, and calcium chloride plays a more significant role in accelerating formation of thaumasite than calcium oxide does. The rate of thaumasite formation increases as the amount of calcium ion increases, while increasing the amount of sulfate sodium and carbonate sodium failed to enhance obviously thaumasite formation. The transition from silicon oxygen tetrahedron of silicate to silicon oxygen octahedron of thaumasite is rate determining step of thaumasite formation. Moreover, calcium ion can improve stability of silicon oxygen octahedron, transition state of thaumasite formation, which results in increasing the rate of thaumasite formation. Therefore, thaumasite formation can be retarded by lowering the amount of calcium ion.