Abstract: Near-field wakes are key factors affecting the safety of aircraft landing and take-off. Accurate characterize these near-field wake vortices is the foundation for further studying the evolution of far-field wake vortices and also the theoretical basis for increasing the airspace capacity by reducing wake separations. The evolution of near-field wake vortices of an A320 aircraft is simulated by solving the Reynolds-Averaged Navier-Stokes equations. Computation methods for the characteristic parameters of near-field wake vortices are compared. Results show that compared to the Hallock-Burnham model, the Lamb-Oseen model can give a more accurate description of the velocity field induced by near-field wake vortices. The average ellipse method is more accurate than the traditional one in calculating the radii of the near-field wake vortices. Results also suggest that it is more proper to use an average circulation between 3 m to 12 m to describe the strength of near-field wake vortices of A320.