Clinical　electroencephalography　(EEG)　plays　a　crucial　role　in　the　research,　diagnosis　and　treatment　of　brain　diseases.　Accurate　EEG　annotations　are　particularly　essential　for　these　purposes.　Existing　EEG　annotation　tools　are　developed　for　specific　research　tasks,　restricting　their　applicability.　To　address　this　issue,　we　have　designed　and　developed　a　convenient　and　efficient　system　for　EEG　annotation.　This　system　supports　both　channel-specific　waveform　annotation　and　channel-independent　state　annotation　with　real-time　visualization　effect.　For　these　two　types　of　annotation,　we　offer　commonly　used　labels　to　meet　the　needs　of　diverse　studies.　Additionally,　the　system　provides　data　conversion　and　preprocessing　capability,　various　visualization　settings　and　sample　browsing　functions,　enhancing　the　user　experience.　The　application　of　this　system　can　accelerate　the　establishment　of　high-quality,　multi-class　annotation　datasets　and　facilitate　brain　disease　research.　©　2023　IEEE.