To study aircraft cruise phase emission, its thrust level was assumed to be set at 70% of maximum thrust. The GEnx-2B67/P engine nitrogen oxides (NOx) emission data in the International Civil Aviation Organization (ICAO) engine emission database was deployed as an example, emission intensity in the flight direction is calculated with the System for Assessing Aviation's Global Emissions (SAGE). Assuming the aircraft emission is a constant line source at the flight direction, which is perpendicular to the wind direction, a cruise phase pollutant dispersion model is developed based on the Gaussian model. Finally, using the ICAO's Peebles data in Ohio, USA in 2012, NOx emission and dispersion were simulated for the GEnx-2B67/P engine aircraft for its cruise phase successfully.