Based on the safety of the air traffic control front-line operation units, considering the increasing flight volume year by year and the large regional differences in the annual flight support volume of each air traffic control operation unit. In order to make the existing safety support capacity of each air traffic control operation unit better match with its flight support capacity, the number of towers, regional support sorties and runways are taken as important attributes to classify the air traffic control safety capacity assessment units. Using the established evaluation index system and TOPSIS ranking method, the rationality of unit classification evaluation is verified by the output results.