Objective The aim was to investigate spatial variation characteristics of woodland soil pH and to find the main influencing factors on soil pH in the Jinsha River Basin in Yunnan Province.

Method A total of 19071 soil samples were collected from woodland in Jinsha River Basin, Yunnan Province. The GIS technology and R language were used to analyze the spatial variation characteristics of soil pH value and the effects of climate, soil and topographic factors on soil pH value.

Result The results showed that the mean of soil pH in the study area was 6.37, showing a normal distribution. The coefficient of variation was 14.9%, showing a moderate degree of variability. The multiple regression analysis and variance analysis showed that the spatial difference of soil pH was mainly influenced by climate, soil type and soil parent material. The difference of soil pH among climate zones was the most obvious, showing soil pH was the lowest in subtropical climate and warm-temperate climate zones. Both soil types and parent materials influenced soil pH significantly. The pH values of yellow soil, red soil, and purple soil were lower than those of other soil types. Moreover, the soil pH values of acidic crystalline rocks, basalts, and argillaceous rocks were lower than those of other parent materials. Compared to climate, the topographic factors had relatively small influence.

Conclusion Comparative analysis showed that the influence of altitude on soil pH was more caused by climatic zone, soil type, texture and other factors. These results had suitable guides on the development, protection and ecological management of soil resources in the Jinsha River Basin of Yunnan Province.