The rules of soil spatial variability in aspect of soil fertility are important indicators to value the soilfertility and they are also important basis to guide precision fertilization. Using Natural Neighbor Algorithm basedon the soil fertility space database, the changing of soil nutrients’ spatial variability in Kaian Town of Nongan Coun-ty was studied after three consecutive years of precision fertilization in 2008, 2009 and 2010. The results showedthat the pictures of soil alkali Nitrogen spatial variability have obviously changed after precision fertilization. From²008 to 2010, soil Nitrogen’s deviation declined to 108 mg/kg in 2008, 87 mg/kg in 2009, 75 mg/kg in 2010, andthe soil Nitrogen content’s area proportion between 110mg/kg to 140mg/kg has increased year by year, which indi-cated that soil fertility’s diversity has become smaller. This has discovered a method to improve the science and ob-jectivity in valuing soil fertility.