Abstract: Shortage of effective potassium and toxicity of Fe2+are important limited factors to rice yield in coldwaterlogged paddy field.Based on the field experiment,the effects of rice growth physiology,plant potassium iron nutrient accumulation and rice yield components were studied in cold-waterlogged paddy field under different potassium utilized in the paper.The results indicated that the content of chlorophyll a+b and photosynthetic ratio could respectively improve 10.53% ~22.67%、27.71% ~48.62% in booting stage under potassium fertilizer increasement,10.53%~22.67%、27.71%~48.62% for root activity improved respectively in booting stage and mature stage.Meanwhile,rice yield could improve 4.93%~14.77%.Potassium fertilizer increased could not only promote the absorption and transportation of potassium,inhibit the iron accumulation of rice root,but only could reduce respectively 0.04~0.73、0.33~0.95 and 0.62~0.82 percentage point for the content of iron in tillering stage,booting stage and mature stage,indicating that it was a significantly negative correlation between rice root potash content and iron content in tillering stage.Potassium fertilizer increasement could improve the root activity,strengthen the photosynthesis,promote the synthetic and transportation of carbohydrates,inhibit the toxicity of Fe2+.So potassium fertilizer increasement could play the production potential for cold-waterlogged paddy field.