A personal computer is used for the control of the electronic and pneumatic units of in-situ measurement of N2O emitted from croplands. The introduce of sample, gas chromatographic analysis and integration of the data obtained are undertaken automatically. The ambient temperature and radiation can also be measured with the automatic system. Air samples are alternatively taken from the static chamber installed in fields. After removing of raoisture and CO2, the sample is injected into GC/ECD system and the N2O concentration in the headspace of each chamber is then analyzed. The variation of N2O concentration in the headspace of each chamber can be obtained by which the N2O emission rate from the area covered by the chamber can be calculated.