Abstract: The feature and change trend of N, Pand Kcycling and balance in farmland ecosystem of Luancheng County at the piedmont of Taihang were analyzed.The status of nutrient balance was appraised, and the rational way to apply fertilizer was put forward. The result indicated that N balance went through a process from slight deficit to surplus during 1985～2000, changing from deficit of 1.4% in 1985 to surplus of 48.6% in 2000. Potassium balance changed gradually from serious deficit of 82% to slight surplus of 4.6%, but was still deficit in many fields. Pbudget was surplus ever since 1985. Comparing with the output of nutrients, the inputs of N and P were excessive, but the Kinput was short. Under the current soil fertility and crop planting structure, the countermeasure to control the application amount of Nand Pand to increase the application rate of Kshould be carried out, so that,there would be no significant surplus Nemitting or leaching from soil into environment. The technique to return crop straw into farmland should be extended to increase the nutrient recycling rate.