Spatial variation of soil pH is important for the evaluation of environmental quality. A reasonable number of sampling points has an important meaning for accurate quantitative expression on spatial distribution of soil pH and resource savings. Based on the grid distribution point method, 797, 700, 594, 499, 398, 299, 200, 149, 100, 75 and 50 sampling points, which were randomly se-lected from 908 sampling points, constituted 12 sample sets. Semi-variance structure analysis was carried out for different point sets, and ordinary Kriging was used for spatial prediction and ac-curacy verification, and the influence of different sampling points on spatial variation of soil pH was discussed. The results showed that the pH value in Kenli County was generally between 7.8 and 8.1, and the soil was alkaline. Semi-variance models fitted by different point sets could well reflect the spatial structure characteristics of soil pH. With the decrease of the number of sampling points, the Sill value of sample set increased, and the spatial autocorrelation gradually weakened. Considering the prediction accuracy, spatial distribution and investigation cost, the number of sampling points greater than or equal to 150 could satisfy the spatial variation expression of soil pH at the county level in the Yellow River Delta. This was equivalent to taking at least 107 sam-pling points per 1 000 km2. The results in this study are applicable to areas with similar environ-mental and soil conditions as the Yellow River Delta, and have certain reference significance for them.