In this paper the influencing factors of farmland soil pH in southwest Hubei Province were studied based on 1 757 Samples of 0-20 cm soil layer collected and measured in 2017. The results showed that pH decreased from northeast to southwest in the study region, and farmland soils were generally acidic. pH values of different farmland types were in the order of irrigated farmland > dry farmland> paddy field. pH values were different in soils derived from different parent materials, it was higher in soil derived from carbonate rock while lower in soil derived from crystalline and argillaceous rocks. Multi-factor integrated model of farmland soil pH showed that human activities were the main influencing factors of soil pH, followed by climate, crops and terrain. Farmland soils with different acidity and alkalinity responded differently to influencing factors, neutral and weakly alkaline soils positively responded to anthropogenic activities, strongly acidic and weakly acidic soils positively responded to crop growth and topography, very strongly acidic soils responded minimally to human activities, and weakly alkaline soils responded maximally to climate.