In order to reduce the wake separation between a ARJ21 aircraft and its front aircraft and to improve the airspace capacity and airport operation efficiency, theoretical analysis and experimental verification were carried out based on the actual detection of aircraft wake vortex data by airport wind lidar combined with the domestic aircraft ARJ21 aerodynamic response model. The aerodynamic force and moment of a ARJ21 aircraft under the action of different front aircraft wake were obtained. The results show that the ARJ21 is in no bump state when follows a B747 with an interval of 9.3km, and the rolling moment coefficient is less than the limit range. When follows a A320 or B737 with an interval of 6km, the ARJ21 is in the state of no turbulence, and the rolling moment coefficient is less than the limit range. The results show that the wake separation of a ARJ21 aircraft has a certain reduction space.