Geostatistics with GIS spatial technology was applied to analyze the temporal and spatial variability of pH in top soil (0-20 cm) for tobacco planting region in Sanmenxia, Henan province. The results indicated that soil pH value ranged form 6.5 to 8.8 and met the requirement to produce high quality tobacco leave, but the pH value in some locations was a little high. The distribution of pH value was logarithm normal distribution, its variance coefficient was 15.2% and 4.5% for 2002 and 2007, respectively. The semivariogram of pH could be best described by the exponential model and spatial heterogeneity of pH was 55.77 km and 92.39 km. The Kriging interpolation method was applied to calculate the unobserved points and was used to generate the spatial and discrepancy map. The reasons that soil pH increased were analyzed and the strategies for soil improvement were also proposed.