Abstract: The descriptive statistics and spatial variation of pH values in the soil of a 22 years old coastal forest ofPinus elliottii E. in Fuzhou were analyzed by the method of geo-statistics after field work. The results showed that the soilwas strongly acidic，with 4.59，4.86 and 4.90 of pH values as well as 5.75%，5.01% and 7.63% of variable coefficients inthe depth of 0-20 cm（Layer Ⅰ），20-40 cm（Layer Ⅱ）and 40-60 cm（Layer Ⅲ）in the soil，respectively. The nuggetvalues were 0.859，0.136 and 1.000，respectively. And the optimal spatial autocorrelation models of pH values in LayerⅠ，Ⅱ and Ⅲ were liner model with sill，exponential model and liner model with sill，respectively. The results of Krigingoptimal interpolation values indicated that soil pH values in Layer Ⅰ and Ⅲ were mainly influenced by structural factorswhile the ones in Layer Ⅱ were partly affected by forest factors. The soil acidity may be due to several reasons such assoil parent material，air acid deposition，soil water content and forests.