The effect of sodium benzoate on the growth and physiological characteristics of wheat seedlings under heavy metal stress was studied on “Yangmai 16”. The results showed that 2.4 mmol·kg^-1 compound heavy metal significantly inhibited the growth of wheat seedlings and delayed wheat seedlings emergence. Under compound heavy metals stress, application of 2-4 g·L^-1 sodium benzoate significantly increased (P<0.01) the chlorophyll content, the chlorophyll fluorescence parameters F_v/F_m，F_v/F₀, and the root activity of wheat，compared to the control (water treatment). Further analysis showed that application of 2-4 g·L^-1 sodium benzoate alleviated the toxicity of wheat seedlings by increasing the contents of free proline, soluble proteins, and the activity of SOD (Superoxide Dismutase), and reducing MDA (Malondialdehyde) content. In contrast, the higher concentration of sodium benzoate solution （＞6 g·L^-1） inhibited the growth of wheat seedlings and even caused damage to seedlings. The correlation analysis shows that when the sodium benzoate concentration was in the range of 1.97-3.12 g·L^-1 (2016) and 1.58-3.27 g·L^-1 (2017), the chlorophyll and its components, root activity, SOD activity, soluble protein, and free proline content were the highest. When the concentrations raised to 2.59 g·L^-1 (2016) and 3.02 g·L^-1 (2017), the MDA content was the smallest. In conclusion, the low concentration （1.58-3.27 g·L^-1）of sodium benzoate could reduce the toxicity of compound heavy metals stress on wheat seedlings.