In view of the fact that at present there is no direct method for observing saline water variating, this paper considers that statistical analysis of electric log might be used to get information on characteristics of saline water migration. For this purpose, the method for calculating variation function in geostatistics and the method for determining dimensions of statistical window in trend surface analysis were introduced to determine areas of divisions.Based on this calculation, in combination of interpolation of time, the variation regularity of the saline water body with time was obtained. In interpretation of statistical results, the hypothesis about the water-releasing effect of viscous soil was introduced and improved. This paper is the first useful attempt at quantitative description of saline water migration characteristics.