Spatial variability of soil salinity and moisture for all depth layers was measured and analyzed by using statistics and geo-statistics

which was performed in characteristic field of Yellow River Delta.The results indicated that soil salinity and moisture for all depth layers were generally high

and salt accumulation at the surface soil layer was significant;Soil salinity for all depth layers exhibited moderate spatial variability

and soil moisture of surface layer exhibited moderate spatial variation while soil moisture of other layers exhibited week spatial variability;Soil salinity and moisture for all depth layers showed moderate spatial autocorrelation resulting from compound impact of structural and random factors.The spatial distribution map of soil salinity and moisture interpolated by Kriging interpolation showed apparently that to some extent there existed spatial correlativity and variability between soil salinity(or soil moisture) distribution maps of different depth layers.The spatial distribution of soil salinity and moisture for surface layer was mostly controlled by micro-topography and climatic conditions

while the spatial distribution of soil salinity and moisture for deeper layers was mainly controlled by groundwater properties.The surface layer soil salinity and soil moisture of corresponding layers were used to estimate soil salinity of deeper layers by CoKriging method respectively

it is shown that the interpolation precision of CoKriging method was higher than that of Kriging method

and the precision of CoKriging estimation by surface layer soil salinity was significantly higher than that by soil moisture

the estimated variance could be decreased by 167.36% compared with that estimated by Kriging method.