The excessive emission of N2O (Nitrous oxide) will destroy the ozone layer, reasonable fertilization and adopting measures of emission reduction of N2O are of great significance to slowing down the greenhouse effect. The article studied the impact of fertilization and water on the emission of N2O from the cabbage farmland using FTIR spectrometry. To enhance the sensitivity of the measuring system, we used multi-reflecting mirrors to increase the optical pathlength. By comparing the infrared spectra between the before and after fertilizer application and the NIST spectral library, finally, the band at 2 160～2 225 cm-1 was chosen as the spectral characteristics band of quantitative calculation of N2O through analyzing. The research found that fertilization and water could promote the emission of N2O from the cabbage farmland soil, which could supply theory bases for emission reduction of N2O and slowing down the greenhouse effect. Finally, we also studied the diurnal emission rules of N2O from the fertilized soil; the results showed that the emission of N2O was lower at night and the results were compared with that of previous’ studies, which verifies the feasibility of this method. The results proved that FTIR with long optical path was a rapid and effective method to measure the emission rules of N2O from the cabbage farmland soil, which can measure the gas emissions of N2O from the fertilized cabbage farmland soil and compared with other traditional measuring methods, it had the advantages such as rapidness and convenience.