Abstract: In order to study reason of widespread pollution caused by nitrogen in paddy field, dynamic change of nitrogen with different forms were analyzed by using organic and inorganic fertilizer with different ratio, according to local fertilization model suitable for rice cultivation. The results showed that, pig manure compost was a proper organic fertilizer for rice cultivation. NH₄⁺-N lost by surface runoff, NO₃^--N by leakage. It could cause severe widespread pollution when manure and inorganic fertilizer with unreasonable ratio was mixed utilized. The manner of nitrogen loss differed in rotten degree of organic fertilizer. Nitrogen loss of fresh pig manure, e.g. leakage and surface runoff, was severe correspondingly. The average amount of NO₃^--N in soil reach the highest level with 13.59 mg/kg in six treatments, while the total amount of NH₄⁺-N, up to 5.65 mg/kg, was lower slightly than that with fertilizer treatment. The total amount of NH4 +-N in surface water after pig manure compost treatment reached 4.52 mg/L, and the average amount of NO₃^--N in soil amounted to 0.56 mg/kg. In contrast to the six treatments, the loss of nitrogen in pig manure compost by leakage was the lowest level. The NH4 +-N amount of surface water with ad residues treatment reached 4.84 mg/L, while the average NO₃^--N content was 2.87 mg/L, indicating that nitrogen loss way of ad residues was surface runoff primarily, and the nitrogen loss by leakage was lower slightly than fertilizer treatment.