This paper deals with a comparative and collaborative study on determining soil total potassium with three fusion or digestion methods conducted by four labortories.The result showed that the average percentage of soil total K value by NaOH fusion method was 98.5% of the value by Na₂CO₃ fusion method,and 99.5% of the value by HF digestion method.The precision and accuracy of the three methods were also very close.Therefore,the authors sugBest that the NaOH fusion method can be used in routine work instead of HF digestion meshod for determining soil total potassium.