[Objective] The aim of the study was to provide theoretical basis for the improvement of saline soils by evaluating the improvements in different spacing treatments of blind ditch in the northwest area. Whereby, the salinization prevailed in the widespread area of Northwest China was expected to be restrain and the lands were expected to be use efficiently.[Methods] Saline soil and Two years old Salix babylonica growing on it was used as the experimental materials. The effects of different blind ditch spacing (CK was control,T₁ was 3 m,T₂ was 6 m,T₃ was 9 m,T₄ was 15 m) on soil physical and chemical properties, the growth, leaf spectral photosynthetic characteristics of weeping willow were studied.[Results] (1) Soil water content, pH value and soil salinity of the four treatments were all lower than the corresponding values of the control. The water content of 4 treatments were significantly different from the control (p<0.05) except T₄. The soil salinity of T₃ treatment decreased the most. (2) All the growth indexes of weeping willow were improved in comparison with those of the control treatment. The effect of T₁ ditch spacing treatment is the best and T₄ treatment is the worst. The differences among T₁ and T₂ and T₃ treatments were not significant(p>0.05).(3) Four kinds of ditch spacing treatment significantly increased the leaf photosynthetic rate(P_n), transpiration rate (T_r), stomata conductance (G_s) and chlorophyll content of weeping willows. The differences among T₁ and T₂ and T₃ treatments were not significant (p>0.05). The effect of T₄ spacing treatment is less than the ones of other three treatments.[Conclusion] Therefore, the ditch spacing treatment can effectively discharge salt. When selecting the blind ditch spacing, T₃ ditch spacing treatment is the best solution for its low economic cost.