The effects of combining organic fertilizer with chemical fertilizer on cotton field N 2O emission flux, emission characteristic and total amount of N 2O emission were investigated by using the static chamber-gas chromatograph method under plastic-mulched drip irrigation. The four-year field experiment consisted of four treatments, including CK, CF, 60%CF+OF and 60%CF+BF (without fertilization as CK, total chemical fertilizer as CF, organic fertilizer as OF and bio-organic fertilizer as BF). The results showed that N 2O emissions with fertilizer supply were significantly higher than that without fertilizer treatment during the growing season of cotton. The order of N 2O emission on the third or fourth days after fertilization was: CF > 60%CF+OF > 60%CF+BF > CK, and a significant difference existed between treatments ( P <0.01) during each fertigation schedule with drip irrigation system. However, treatments with organic fertilizer combined with chemical fertilizer increased N 2O emission compared with chemical fertilizer treatments on the seven or eighth days after fertigation. In addition, when all irrigation and fertilization schedules were finished, higher N 2O emission flux was always observed with treatments supplied with organic fertilizer in contrast to that with chemical fertilizer application. The highest amount of total N 2O emission in the cotton growing season was found in CF treatment. Compared with CF, the treatments of 60%CF+OF and 60%CF+BF decreased N 2O emission by 3.75% and 8.37%, respectively. It was found that N 2O emission factor (EF) was also decreased by 1.39% with 60%CF+OF treatment and by 73.8% with 60%CF+BF treatment. Meanwhile, path analysis showed that N 2O emission was more closely related to soil NO - 3-N content than to NH + 4-N content.