The invention discloses a method and a device based on wave field illumination design observation. The method comprises steps of performing screening on an obtained target area or a corresponding first wave field illumination record to obtain a second wave field illumination record, utilizing the second wave field illumination record to obtain illuminance data of an object layer in the target area, performing correlation coefficient calculation on the obtained illuminance data, and optimizing and designing observation system parameters applicable to the target area according to the calculation result. The invention can realize a quantitative optimization design observation system.