The purpose of study is to investigate the current user interface level of air traffic control system with the usability analysis and satisfaction survey questionnaire on user satisfaction. Think aloud protocol is used to identify not only task analysis, but also the level of user-friendliness of the FIMS and ASDE system, and the user interface questionnaires was conducted by QUIS. We collected data from 6 controllers for Think aloud protocol and 15 controllers for QUIS in Incheon airport. The results showed that the system was the valuable tool for ensuring human performance with the support of memory and the facilitation of decision-making tasks. It helps air traffic controllers perform better and minimize errors in a congested time. The human-computer interface system design, however, was not applied, which led to the increase of workload. Air traffic controller participation in software development provided excellent examples for applications in terms of software in FIMS. Based on these results, the study provided that the usability of system interface was necessary to take into account human factors. The development and design of system was discussed in User Interface environment.