Oxyfertigation delivers water, fertilizer and gas coupled mixture to crop root zone via subsurface drip irrigation system. This new technique changes the oxygen concentration and water distribution in soil and thus affecting the nitrogen cycling process, including nitrification and denitrification, and then affecting soil nitrous oxide (N2O) emissions. However, the influences of oxyfertigation on soil N2O emissions from greenhouse vegetable fields and its main influencing factors were both little known. To understand the influence of aeration, nitrogen application and irrigation on pepper soil N2O emission in greenhouse, totally eight combinations were tested, including two types of nitrogen application rates (300kg/hm2 and 225kg/hm2), two types of aeration levels (40mg/L and 5mg/L), and two types of irrigation amount (1.0W and 0.6W, W was full irrigation amount). Soil N2O emission flux was monitored via using static chambergas chromatograph technique. Soil temperature, waterfilled pore space (WFPS), dissolved oxygen (DO), NO-3N and NH+4N content were also measured. Quantitative contribution of influential factors to N2O emission under oxyfertigation was analyzed by structural equation model (SEM). Results showed that aeration, the increase of nitrogen rate and water amount resulted in an increase of soil N2O emission peak, cumulative N2O emission and yieldscaled N2O emission under oxyfertigation. Compared with control, the cumulative N2O emission of aeration condition was averagely increased by 31.90%. The cumulative N2O emission under full irrigation was averagely increased by 43.22% compared with deficit irrigation. Similarly cumulative N2O emission under conventional nitrogen rate was averagely increased by 33.01% compared with the 75% conventional nitrogen rate treatment. Aeration and the increase of water amount resulted in an increase of crop nitrogen use efficiency. However, the increase of nitrogen rate caused a decrease of crop nitrogen use efficiency. Considering crop yield, nitrogen use efficiency and yieldscaled N2O emission, the treatment of 75% conventional nitrogen rate aerated deficit irrigation was an optimal combination under oxyfertigation. The path coefficients of soil temperature, WFPS and NO-3N content were 42%, 60% and 58%, respectively. And soil temperature, WFPS and NO-3N content were identified as main influential factors. The research result provided a reference for the selection of water, gas and nitrogen coupling management and demonstrated the great significance in knowledge of soil N2O emission under oxyfertigation.