The geochemistry survey analysis was conducted on the soil samples from the Huai’an city in the years of 2004 and 2019，to explore the spatial variation characteristics and influencing factors of soil pH. The results showed that the soil pH value ranged from 4.66 to 9.46 in the study area in 2019，with an average of 7.95. The overall performance was low in the south and high in the north，the coefficient of variation is 0.095，indicating weak spatial variability. The geostatistical analysis results indicated that the optimal theoretical models for the variation function of soil pH were both exponential models in the study area in 2004 and 2019，with block gold coefficients of 0.283 and 0.352，respectively，it indicated that soil pH values had a moderate spatial correlation due to the combined influence of human and structural factors. The analysis results of cold and hot spots showed that，in 2019，there was a significant increase in areas with high soil pH values compared to 2004，and the range of areas with low soil pH values further expanded，with more significant spatial clustering distribution. Correlation analysis showed that the main controlling factors for the spatial variation of soil pH values in the study area were geomorphic type and soil type，which could independently explain 40.9% and 21.7% of the spatial variation of soil pH values in the study area，respectively. In addition，soil pH was significantly positively correlated with calcium content，and significantly negatively correlated with nitrogen，sulfur，and organic matter content. In the past 15 years，the soil of the Yellow River floodplain in the research area has slightly alkalized，and the soil of the Hongze Lake floodplain and low-lying plain area of Lixia River has slightly acidified. Corresponding measures need to be taken to regulate the soil pH.