Abstract: Lead (Pb) contamination of soil poses severe health risks to humans through vegetable consumption. In order to reduce the lead bioavailability of lead-contaminated soil, alleviate lead harm to crops. A soil pot experiment was conducted to investigate the effect of magnesium fertilizer on lead bioavailability of soil. The trial crop is spinach (Spinacia oleracea L.). The experiment design was the randomized complete block with four replications. Three rates of magnesium fertilizer (75, 150, 300 mg/kg soil) and two lead concentrations (125, 1000 mg/kg soil) were employed. The results showed that the different lead concentrations had significant influence on the growth, fresh yield and nutrient uptake of spinach. The stronger of lead concentration, the grater of lead harm to plants. Appropriate application of magnesium fertilizer in lead-contaminated soil can promote spinach growth, increase fresh yield, enhance the contents of leaf chlorophyll and vitamin C, and increase the amount of N, P and K absorbed by spinach plants. Correlation analysis revealed that the relationship between the amount of magnesium absorbed and the amount of lead absorbed by spinach plants was significantly positive correlation. This study indicated that appropriate application of magnesium fertilizer can reduce lead bioavailability in the lead-contaminated soil, alleviate lead harm to plants, increase production and improve quality. It has certain direct function to improve slight lead-contaminated soils and high yield and high quality production of spinach.