Using basic statistics, geo-statistics and GIS methods, soil salinity spatial variability and homogenizing effect to heterogeneous soil salinity under rainfall leaching and subsurface drainage during the rainy season were studied. The main results showed that: 1) Spatial variability in soil salinity could be decreased significantly under rainfall leaching and subsurface drainage during the rainy season. The coefficient of variation (CV) dropped from 48.13% to 28.14%, and nugget effect value (C0/( C0+C)) decreased from 72.86% to 59.42%; 2) Spatial variability of soil salinity showed a homogenizing tendency. Soil salinity less than 7 g/kg (79% of samples) homogenized to within 1.5 ~ 2 g/kg under rainfall leaching and subsurface drainage during the rainy season, in this extent, the ratio of soil desalination was positively correlated with the initial soil salinity, whereas that more than 7 g/kg was a negative correlation; 3) The homogeneity was also reflected in transformation of salinity grade at different areas. Before rainfall leaching and subsurface drainage, the moderately and heavily saline soil area dominated the pilot field; after rainfall leaching and subsurface drainage, the mildly saline area was dominant. The amount of soil salt discharge was 67.78 t in which heavily saline soil area constituted 91% and mildly contributed –35.01% affected by leaching of rain water and subsurface drainage.