The solubility of sodium chromate tetrahydrate has been investigated in the temperature range from 290.15 K to 325.15 K using the conventional polythermal method by means of the laser technique. The metastable zone width (MZW) and the apparent nucleation order of sodium chromate tetrahydrate were calculated. The effects of cooling rate, initial composition, stirring rate, and seed particles on the MZW were also studied. The results show that the MZW of sodium chromate tetrahydrate first increases and then narrows with increasing initial composition. The MZW becomes wider by reducing the cooling rate and the mass of seed particles, whereas the MZW will be reduced by enhancing the rotation frequency of stirring and the diameter of seed particles.