Abstract:【Objective】Significant changes have recently taken place in the agricultural planting structure of the purple paddy soil area. These changes have profoundly affected the form and dynamic balance of soil potassium. Thus, understanding the impact of land-use changes on the evolution characteristics of different forms of potassium in purple paddy soil is of great significance to regional potassium management and environmental protection. 【Method】In this paper, we analyzed the dynamic characteristics and influencing factors of different forms of potassium in the purple paddy soil after abandonment, dry farming and conversion to fish ponds, using the time series method. 【Result】The results showed that abandonment and dry farming reduced the water-soluble potassium content of purple paddy soil, and conversion to fish ponds increased the water-soluble potassium content of purple paddy soil. Abandonment, dry farming and conversion to fish ponds could all increase the exchangeable potassium and non-exchangeable potassium content of purple paddy soil. Both the increasing magnitude and rate are highest for dry farming, intermediate for abandonment, and smallest for fish farming. 【Conclusion】In the purple paddy soil, potassium in different forms reached a general balance after 5 years of fish farming or 12 years after abandonment. However, after 20 years of dry farming, the different forms of potassium in the soil did not reach a general balance. The results also showed that the release of mineral potassium in purple paddy soil was relatively fast in the natural state. After the land-use changes, there were complex connections between the occurrence and dynamic balance of purple paddy soil, the loss of soil organic matter, and the transformation of soil clay minerals, which needs further research.