Air traffic controllers (ATC) play critical roles in aviation operations, and their fatigue levels have a direct impact on safety and efficiency in the industry. A multifaceted approach is adopted for the purpose of evaluating fatigue levels, encompassing various indicators such as reaction time, pupil diameter, electroencephalography (EEG), and the Stanford Sleep Scale (SSS). Subsequent to data collection, a series of paired-samples t-tests are conducted for the purpose of data analysis. The results obtained demonstrate a clear increase in all indicators, thus indicating that the fatigue level increases after the shift. In light of these findings, a comprehensive assessment approach for ATC fatigue, termed CAAF, is proposed, which incorporates all relevant indicators. The Pearson related coefficient between CAAF and SSS is remarkably 0.439, attesting to the effectiveness of the proposed approach on ATC fatigue assessment.