Nitrogen loss from farmland is one of the main contributors to agricultural non-point source pollution. Nitrogen leaching loss due to excessive fertilization is the major nitrogen loss. A laboratory experiment and field monitoring were conducted to investigate nitrate nitrogen leaching dynamics under extensively agricultural systems and local management. Results showed that soil nitrate concentration did not change frequently in the intensive planting areas and in the conventional planting areas, but both changing ranges were greater. Monitoring results of field experiment indicated that the difference of groundwater nitrate-nitrogen content in three typical planting areas was distinct; nitrate nitrogen average content of greenhouse vine intensive planting base was the highest among three typical planting areas, being up to 11.2mg/L. However, nitrate nitrogen content of vegetable intensive planting areas and conventional planting farmland were 4.02mg/L and 1.35mg/L respectively. It further suggested that nitrate nitrogen average content in intensive planting areas had large varied amplitude and higher over standard rate, and excessive irrigation and fertilization had caused groundwater environment pollution. The study is also believed to be useful in formulating management strategies for an extensively planting farmland to reduce diffusive pollution from agricultural activities.