Abstract: Factual water consumption status of Sophora japonica L.sprayed with different concentrations of plant growth regulator Shifengle" solution including 10, 20 and 40 mg/L(water is control) was studied by using BP3400 Precision Balance etc.Leaf water potential was measured using pressure chamber in different phases.It was indicated that S.japonica L.was low-water-potential, dehydration-resisted, drought-resisted species, and the equation of the relation between water potential and soil moisture content was y=0.018 2 x²-1.071 3 x + 16.52(R²=0.998 7).Under the same moisture content conditions, water consumption rate of control was 10.2%(-) 82.7% higher than that sprayed by "Shifengle".With the drought stress increasing, water potential of control sharply diminished, but the treated remained high water potential.