Acomparison has been made of the discrepancies between the observed NO+O continuum intensities from the horizontal scanning photometer aboard the OGrO-6 and the calculated intensities with Ovalue based on the Chapman excitation mechanism and NOdata from Meira's measurement.These results seem to show an indication that the excitation mechanism of airglow green line could be in accordance with the relation of J∝[O]
2 but not J∝[O]
3 as in Chapman's mechanism.