Abstract: Based on National Supervision Base for Aqui-cinnamon Soil Fertility and Fertilizer Benefits in Changping, Beijing (1991-2003), the effect of long-term fertilization on N and oranic matter dynamicchanges in fluvo-aqvic soil，the main results obtained：the combined application of NPK with organic materials can increase soil total N content obviously. Both two treatments of NPKM and NPK + straw increased total soil N by 21.11% and 14.35%, respectively, which was higher than that of chemical fertilizer alone markedly. Compared with CK, long-term application of N, NP, and NPK increased soil total N by 10.03%, 8.32% and 8.40%, respectively, while PK treatment decreased soil total N content. Meanwhile, long-term application of N only, NP, NK and NPK increased content of available nitrogen by 17.26%, 21.55%, 23.83% and 26.41%, separately; Both two treatments of NPKM and NPK + straw were greatly superior to the treatment of those chemical fertilizer alone, with the increment of available nitrogen by 34.97% and 32.96%, respectively. The content of soil organic matter(OM) of NPKM treatment was higher than that of single chemical fertilizer treatment significantly. In comparison with CK, soil OM with treatments of NPK + Straw, NPKM, NPK, NP and N only increased by 7.90%, 14.56%, 6.51%, 5.89% and 2.56%, respectively. Therefore, balanced application of N,Pand K, and combined application of NPK with organic materials play a very important role in improving soil OM status.